Fixed issue #6 (not optimal)

The layouts for the text blocks are not cleaned up when the blocks are
removed from the document because they are linked to the console display
map. This fix is not the fastest way to execute the display code, but it
does still allow the layouts to be used in hit tests.
Added tracking of execution times

Any accelerator, alias, trigger, or timer will now track average
execution times during a session.
Added tracking of times evaluated

Any alias or trigger will now record how many times its pattern is
checked for a match during a session.
Trigger statistics display

The trigger editing dialog will now show session statistics for the
trigger.