Scripts in menus:

- now the file .Bpymenus is in ~/.blender/, please delete the old one
- both ~/.blender/scripts/ and (if set) user pref scripts dir are scanned for scripts
- 2 scripts of the same group with the same name, one in each dir: user pref overwrites the other's entry
- fixed the problem with trailing backslash, was my fault (used NULL instead of "/" for relbase in BLI_make_file_string
- slightly changed msgs to be less verbose and parsing to be more forgiving
- if a script registers with a wrong group, 'Misc' is used instead
- 'Blender' tag is now checked, gives a warning (notice) msg if script is newer than Blender program

Blender.NMesh module and doc:
- added vertex.sel var to get/set selection state of vertex.