Data source
-----------
Datas sources are used as bridge between ES and UI (see General file). Data sources have 
structure like a database. Some table, where are some columns and lines.

    General source
    --------------
    General source provides list of properties which are available in given data source object.

    Data sources are divided into 2 parts:

        1. data source itselfs
            doesn't provide _REAL_ datas - it is just 'template' - it need to be 'created'
            by using some alias which then provides real datas. It can provide only 'list' 
            of all items (which then can be used to create real data source)

        2. instance of source
            created from (1) using alias name

    Defined columns:

        1. Alias
            Used while referecing property
        2. Type
            Prioerty type (general)
        3. TypeFlags
            flags related to type
        4. Callback
            callbacks for get/set
        5. Flags
            general  flags

        Types
        -----
        Every property need to have some 'base' type.
     
            1. int
                integer
            2. float
                float
            3. list
                list which can consists of more types
            4. string
                string
            5. data source
                another data source
        
            Values list
            -----------
            Values list are basically 2 tables. First defines all available types and second
            physical list. List can be single selcatable or multi selectable (flags)

                Type table
                ----------
                    1. alias
                        alias used while referencing column
                    2. text name
                        text name which user see in 'header'
                    3. type
                        same as above

                Data table
                ----------
                Physical list. Number of columns is equal to length of type table

    Example:

        IT data source

        alias      |    type     |   description
        -----------|-------------|-----------------------------
        ins        |  data src   |   list of all instruments
        name       |  string     |   song name
        ...

        ins data source

        alias      |    type     |   description
        -----------|-------------|-----------------------------
        alias      |  string     |   ins alias
        name       |  string     |   instrument name
        provider   |  string     |   instrument provider name
        envelopes  |  data src   |   envelopes
        events     |  data src   |   events
        scripts    |  data src   |   scripts
        ...

        envelopers data source
    
        alias      |    type     |   description
        -----------|-------------|-----------------------------
        points     |  data src   |   physical envelope points
        connection |  list       |   type of points connection
        loops      |  data src   |   loops
        vib_frq    |  int        |   vibrato frq
        ...

        So, in real, if we want to edit 'vibaro' freq, the only thing we need to do is
        create editor box, connect to 'relevant' data source and set item to 'vib_frq'
        
There is some root base data source (such as 'song list'). All other is hierarchy of
data connected data sources.

EXAMPLE: defition of 'sample manager' (simple version - not real)

    +----------------------------------------------------------------+
    | |new| |delete| |sort|                                      |X| |
    +----------------+-----------------------------------------+-----+
    | sample 1       |       _____________                     | __  |
    | sample 2       |      /             \                    | ||  |
    | drum           |     /               \                   | __  |
    | vzuuum         |    /                 \                  | ||  |
    | booom          |    |                  |                 | __  |
    | bleeee         |    |                  |                 | ||  |
    |                |    |                  |       /\        | __  |
    |                |   /                   |______/  \       | ||  |
    |                |  /                               \      |     |
    |                | /                                 \     |     |
    |                +-----------------------------------------+-----+
    |                | |copy|  |paste| |cut| |normalize| |load|      |
    |                |                                   |save|      |
    |                | |size: 12345|                                 |
    |                | |frq:  44100|                                 |
    +----------------+-----------------------------------------------+

Window have PRIVATE 'sample source instance' called 'smp'. For this data source we need
    access 'instrument providers' of general data sources - and if there is alias
    'wave' by which we can assec 'samples' which we need. If there is not 'wave' record
    then song doesn't have created wave ip - and window stay empty. Global data sources
    are passed while creating and can be also changed runtime (menu, whatever).
Sample view connected to 'smp.data'
Size connected to 'smp.size'
etc.