activated() is old qt3 support signal use triggered()
qt4 still has activated for combobox, too much search and replace
cmake: remove unittest option

Create a CMake project just for unittest in the tests folder
MainWindow: Update execute query table view when no results returned

Also update the table view widget and the status message in the Execute
Query tab of the main window when the query was valid but returned no
results.

Fixes #38.