Removed declaration of filesep, not needed.
Added if statement to deal with future removal of DrawMode
Changed reference to vmt_version to correctly open user guide. Change
open command for library functions to work on OS X.
Updated Help menu callbacks

- Change reference to vmt_version to correctly open user guide.
- Change open command for library functions to work on OS X.
Revert "Changed reference to vmt_version to correctly open user guide. Change"

This reverts commit 84de8b522400b2d7dcf96cd59f6e18e4f22a2eb5.
Revert "Revert "Changed reference to vmt_version to correctly open user guide. Change""

This reverts commit a8df5a80cef64868f96188f37a8538bfab9e3a80.
Merge branch 'testing' of https://github.com/moffat/VMT into testing
Merge branch 'moffat-testing'