#16 Make user preferences persistent

[Mike Kelly]

Currently, any changes that the user makes with
regard to allocation rule weights, window size etc.
are lost once the application is closed. It is
desireable that these user preference be persistent
across runs since it is likely that the user will
want to have the same settings each time the
application is executed. These preferences would
include the following items:

1. Window sizes
2. Allocation rule weights
3. Preferred allocator
4. Last known user directory
5. Perferred schedule data export format (xml, csv,
etc.)

Note that more items could be added as more features
are added to the application.