Merge branch 'mergecocos3.0' of https://github.com/houguohua/cocos3d-x into HEAD

Conflicts:
	cocos3d/C3DRenderSystem.cpp
	cocos3d/C3DRenderSystem.h
	cocos3d/proj.win32/libcocos3d.vcxproj.filters
1:remove C3DSamplerMgr
2:change the base class of the C3DDepthTarget and C3DRenderTarget
3:add reload method for C3DVertexDeclaration