Terrain with hardware tessellation, hotfixes

Render:

• Terrain has been migrated from strips to simple triangles, from now on it supports hardware tessellation (only in DirectX 11 and OpenGL 4.0).
• Added a sample with terrain smoothed via hardware tessellation: data/samples/objects/terrain_01.
• Added distance-based gradual projection fading for decals.
• Added a sample with omni-directional decals: data/samples/decals/omni_00.
• Decals use their own 'two-sided' setting during projection rather than material one.
• Skinned meshes can be rendered into the velocity buffer for motion blur.
• Added a sample with translucent lightmaps: data/samples/lights/lightmap_01.

Tools:

• Fixed skinned mesh export in Maya plugins.
• Lightmapping tool inside of the UnigineEditor currently factors in light masks, shadow flags, two-sided option and translucence.
• Fixed clamp/level feature in NormalMapper.
• MeshViewer now shows the number of active bones in a selected surface.
• Added light and viewport masks for decals into UnigineEditor.
• Fixed OBJ files loading in Terrain tool.

Other:

• Fixed splash screens called within init()/shutdown() functions in the system script.
• WorldTransform has acquired new functions that allow to directly access its spline.
• Added support of PPM P2/P3 image file formats.
• Fixed the disappearance of wheels connected by JointWheel.
• Fixed the error after multiple calls of WorldTransform::play().
• Various WorldExpression bugfixes.
• Fixed WidgetFlash positioning.
• Added cross() for ivec3 in UnigineScript.
• Added support of button events in Flash (onRelease, onPress etc).

Documentation:

• Added info on Flash usage.
• Updated UnigineScript library documentation.
• Updated info on core math, data types and operators in UnigineScript.

PS: Mac OS X support is on the way.