Changed to use a SQLite database

Swapped the data provider to SQLite.  The database is now a file in the
output directory (also in the source code) called ExileStash.s3db.  This
database has no constraints other than primary keys.  Overhauled the
code base to handle the new database.

Refactored the way Affixes and Mods are stored.

Refactored so that the item is scanned once and all relevant details are
stashed at that point, rather than multiple passes through to duplicate
work.

Added a new pop up screen with more information (WIP).

Fixed numerous bugs.