Update use of L10NSharp.LocalizationManager.Create

The create process was changed so that the directory of modified TMX
files now a relative path and L10NSharp determines the correct place
to store the files.  The users of Chorus.ChorusSystem.SetUpLocalization
need to change the path to be relative instead of a full path.
Merge pull request #3 from sillsdev/L10NSharpWithRelativePathToUserTmxFiles

Update use of L10NSharp.LocalizationManager.Create