feat: add translation context for operators and their properties.

- 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

bbp_ng/OP_EXPORT_virtools.py

@@ -11,6 +11,7 @@ class BBP_OT_export_virtools(bpy.types.Operator, UTIL_file_browser.ExportVirtool
     bl_idname = "bbp.export_virtools"
     bl_label = "Export Virtools File"
     bl_options = {'PRESET'}
+    bl_translation_context = 'BBP_OT_export_virtools'
 
     @classmethod
     def poll(cls, context):