GSC Reader v1.3

Changelog:

1. Replaced JFrame in displayProgress() method with a JDialog.
2. To prevent multiple progress dialogs from opening, the window is disabled until progress is finished (originally included in the previous version's code, but didn't work as intended).
3. File choosers will remember the last opened directory DURING runtime, not prior (because having to make an ini file to store directories, temporarily or not, is so inconvenient).
4. To prevent index out of range exceptions, all read offsets and sizes (shorts) are now unsigned.
5. To prevent index out of range exceptions, offsets that point to nowhere (outside of the GSDT) will be set to -1.
6. To prevent index out of range exceptions, parameter IDs above 440 will be labelled as invalid.
7. Made GSC file check more lenient (by increasing the max. file size limit from 24 KiB to 36 KiB).