Allow create connect nodes on editor.
Delete unused 'rough' and 'coated' properties.
Apply some style code changes.
Make out the 'enum' options for  reflectance modes.
Change name for material property class.
Show 'use nodes' option on panels.
Add 'translucent' node definition.
Eliminate 'rough' and 'coated' options.
Add some comments and apply style code.
Merge branch 'merge_SSS' of https://github.com/TheBounty/Blender-Exporter into merge_SSS

Conflicts:
	prop/yaf_material.py
	ui/prop_custom_nodes.py