Bugfix

Fixed bugs with the scrollbar --- it now works properly.
Added StatsScreen, bugfixxes

Added a stats screen, which functions very similarly to the
upgradesScreen. (Reused much of the same code)

Fixed glitches with the scrolling; it now scrolls propelry

Fixed glitches with buttons not properly detecting click locations (They
were detecting it based off of where they were originally set to be
located at, not accounting for their offsets...)

Now the stats items, and the upgradeitems will display their heights
based off the location of the bottom text (description), instead of
saying they will all always be 200 pixels tall.