Merge pull request #12 from l1ll1/master

definitively identify the Key in KeyModel.

I'm merging this pull request, but we still need to address this issue:

DEBUG:launcher:KeyModel.removeKeyFromAgent: Traceback (most recent call last):
  File "/Users/wettenhj/Desktop/cvl_github/chris2/cvl-fabric-launcher/cvlsshutils/KeyModel.py", line 521, in removeKeyFromAgent
    if self.pubKey in key:
TypeError: 'in <string>' requires string as left operand, not NoneType
Moved self.pubKey=None to its correct line in removeKeyFromAgent().
Updated comments in deleteRemoveShutdown() and avoided calling
removeKeyFromAgent twice.
Fix for annoying "Command Prompt" pop-up windows.  This was
already fixed in LoginTasks.py, but not in sshKeyDist.py.
Ensuring that busy cursor is turned off when showing modal dialogs.
return the ability of an sshKeyDist.cancel to show an error dialog