file notification service: proxy addObserver to the main thread

(integrated from komodo (trunk) change 83493 by toddw)

git-svn-id: http://svn.openkomodo.com/repos/openkomodo/trunk@14143 b87d16e7-d29f-4ee1-b5ec-817d645d335f
file notification service: remove unused imports

(integrated from komodo (trunk) change 83494 by toddw)

git-svn-id: http://svn.openkomodo.com/repos/openkomodo/trunk@14144 b87d16e7-d29f-4ee1-b5ec-817d645d335f