Add several features for Python API

1. Make ability get current transform orientation matrix.

Like: "bpy.context.scene.transform_orientation_slots.current_matrix" Even we have GLOBAL as current transform orientation

2. Get Current Trasform PivotPoint.

Like: "bpy.context.scene.transform_pivot_point" and return None if selections are empty, because sometimes need check there is selection

Now using Blender Python API impossible create the draw function and drawing something using current selection (creating a bmesh and iterating over each element is too expensive)