Merge pull request #86 from thomthom/master

Fix bug where file unicode flag wasn't being used.
Added menu validation proc for empty model.

Resolved #88
Remove "Export entire model" prompt on export.
Removed messageboxes on import.
Indenting
Pruned .strings files of unused texts.
More pruningof .strings files.
Merge pull request #89 from jimfoltz/iss-24

Fixes #88 and #24.