A couple fixes

The main correction in this pull request is in -[ROI clickInRoi:::::], as you can see in commit a6e2979: OsiriX was using the wrong accessors to get the size of tLayer ROI bitmaps.
Commit 47f22ca modified MainMenu.xib, and I know this can be very annoying. Commit 564cda6 reverts this change, so MainMenu.xib is left untouched.
The other change is made to remove some warnings about an old N2 -[NSView layout] method now colliding with Autolayout APIs. The N2 method (and variables) has been renamed to n2layout. No known plugin is affected by this change.