Set java options to increase permgen size and enable concurrent mark sweep class unloading. This should resolve crashing issues people are having with mod packs with many mods installed.

Signed-off-by: Ross Allan <rallanpcl@gmail.com>
Merge pull request #559 from nallar/master

Set java options to increase permgen size and enable concurrent mark sweep class unloading. This should resolve crashing issues people are having with mod packs with many mods installed.