Add code for use with 'merge_SSS' core branch.
Add 'libstdc++-6.dll' to list of load libs. Since now, this lib is need for the exporter if use MinGW builds.
Merge branch 'master' into merge_SSS
merge master into merge_SSS
Add code for custom material nodes from local repository:
    - this is a most primary implementation of  material nodes
    - Add, register and unregister, news "imports" for custom nodes
    - Add "yaf_custom_nodes.py" file contain new definitions for nodes.
Merge branch 'master' into custom_nodes
Merge branch 'master' into merge_SSS

Conflicts:
	io/yaf_integrator.py
Solve conflict for fix indentation error in AO
after merge from master
Delete comments and add some description text.
Rename 'yaf_mapworld_type' variable to 'bg_mapping_type'
Expand checkSceneLights() function.
Delete unused 'use_color_management' from presets.
Change 'yaf_mapworld_type' variable  name  to 'bg_mapping_type'
Change some old project names.
Re-define some style code.
Uncomment UV layers code: now this feature is work ( new more test..)
Change some panel names ( delete old project references..)
Applied mapping variable change name.
Hide some panels for 'texture background' mode.
Change  some variable names:
    -'tex_in' variable  for more explicit 'mapName'.
    - diffRoot to 'maskRoot' for texture mask slot in Blend material.
    - 'diff_layer' to 'mask_layer' in Blend material.
Refine code for 'negative' and 'noRGB' variables.
Change some style code.
Fix error in last commit
Update Blender version compatibility
Add 'phaseFunction' and 'sssPresets' variables for SSS.
Sync some variable names by core 'registerFactory' value names
Add 'use_limited_texture_context' variable from Blender.
Add SSS texture slots.
Add 'phaseFunction' and 'sssPresets' UI items for SSS
Change some UI explicit descriptions for SSS items.
Begin work for create a new 'Render passes' UI panel:
    - move some elements from 'General settings' to 'Render passes'
    - create a new 'Stamp' UI' group for 'Draw parameters' options.
    - move 'Draw parameters' items to new group inside 'General settings'.
    - move 'Gamma out' item to 'Image out' panel
Clean up SSS code.
Sync integrators type names from 'Core' names.