Merge pull request #50 from Grinch/patch-1

Revamp of Launcher GUI
Merge pull request #51 from Grinch/patch-1

Adjusted Progress Bar size/location
Merge pull request #52 from Grinch/patch-1

OS X needs love too! Close/Min/Options button fix
Switch to DownloadURLConnector
Remove MD5 hardcoding for MC/MC-libs
Fix LWJGL md5 checks
No specific OS
Fix Form locking and progress bar text oddities
Signed-off-by: Steven Downer <Grinch@outlook.com>