Be more tolerant when there is no user interface
Be more tolerant when there is no user interface

If the UIService is included in the application context, but no valid
user interface (IUserInterface) is found, the UIService should still
behave gracefully. In other words, we must check for null.

This used to be revision r4892.

TehSAUCE/imagej,TehSAUCE/imagej,biovoxxel/imagej,TehSAUCE/imagej,biovoxxel/imagej,biovoxxel/imagej