tcl.ui: Modernize code a bit.
 
* ViewerSorter -> ViewerComparator.
* Enable save actions.
* Listener to Adapter when not all methods are implemented.
* Removed dead code.

Change-Id: I72a455367d67693b7d7c9c8e80f4b4cdc405ba49
Signed-off-by: Alexander Kurtakov <akurtako@redhat.com>