Changed workflow answer queue from a static-sized array to a growing
ArrayList.

Change the workflow answer queue from a static-sized array to a growing
ArrayList. This makes for much faster initial loading of the GUI, and
removes the hard cap on answer queue size.
Added missing menu mnemonics. (Issue #45)
Implemented saving of sort method and hide question state.

The hide question state is now saved to the settings file to persist
between sessions. (Issue #43)
The current sort method is now saved to the settings file to persist
between sessions. (Issue #44)
Fixed bug where changing the sort method by clicking on the header did
not change the selected sort in the menu.
Changed location of setting file to user's home directory.