- add translation context for operator, menu, panel and etc. and their associated properties.
- improve some name and description but not finished.
- move reset BME material function inside BMEMaterialsHelper.
- rename variable of collection visitor in BME adder operator for clear meaning.
- replace some message box to report in ballance elements reset operator, BME materials reset operator and rail UV operator
- finish uv section of doc.
- fix issue about the wrong calc of coordinate system axis vector in flatten uv (change it from left hand to right hand).
- fix rail uv display text.