overlay-v1.5.1

This release is all about backend work.

Features:

• Now runs on the latest Java version, and you don't need to install it yourself anymore.
  To run Overlay, simply execute run.bat as usual. You may reuse your config.conf file from v1.5.0.
• Ditched the Win32 version as a result of the above listed changes. No more confusion between the two versions.

Improvements:

• CDragon assets are now updated much, much faster than before (3-4 times faster)
• Various other performance improvements and bugfixes.