Add OS constants and tester to swizzle.
Add a test for the OSVERSION macro to ensure it isn't already defined.
Merge branch 'master' of https://github.com/lksoft/MailCommon

# By Scott Morrison
# Via Scott Morrison (2) and Scott Little (1)
* 'master' of https://github.com/lksoft/MailCommon:
  reverts change where MCC would ignore localized html files when loading.
  removes submodules that may not be necessary.
  removes submodules that may not be necessary.
  Add methods for localizing contents of elementIDs by using string files for table.