CP-5752: Moved ShowColumns functionality from the SearchOptions dropdown menu to
a button at the top left of the search output panel.

Signed-off-by: Konstantina Chremmou <konstantina.chremmou@citrix.com>
CP-5752: Moved Save Search functionality from the SearchOptions dropdown menu to
a Save button in the Searcher panel. Moved collapse Searcher panel functionality
from the SearchOptions dropdown menu to a Close button in the panel. Use new
Expanded property to query the state of the Searcher panel (instead of Visible).

Signed-off-by: Konstantina Chremmou <konstantina.chremmou@citrix.com>
CP-5752: Use Action delegate instead of EventHandler when there is no need to
pass in parameters when the event is fired. Moved QueryElement.Dispose method
from the Designer.cs to the main file (it needs visibility since it contains more
code than the autogenerated method).

Signed-off-by: Konstantina Chremmou <konstantina.chremmou@citrix.com>
CP-5752: Moved ExportSearch method from the MainWindow.cs to the Search tabpage where it belongs.

Signed-off-by: Konstantina Chremmou <konstantina.chremmou@citrix.com>
CP-5752: Removed the SearchOptions DropDownButton and moved the functionality of its items to separate buttons.

Signed-off-by: Konstantina Chremmou <konstantina.chremmou@citrix.com>
CP-5752: Renamed default search. Use Action delegate instead of EventHandler when
there is no need to pass in parameters when the event is fired. Minor code tidy.

Signed-off-by: Konstantina Chremmou <konstantina.chremmou@citrix.com>
CP-5752: Renamed "Add Group" button to "More", changed its image and moved it closer
to the other grouping buttons.

Signed-off-by: Konstantina Chremmou <konstantina.chremmou@citrix.com>