Merge pull request #803 from jikuja/fixes_for_v1.4.0

CHANGED: minor fixes to map and texturepack pane
allow mojang DL's from bundled pack jsons
set local location for libraries downloaded via the pack json
split mc versions from correct variable
multiple MC versions per pack now function correctly, as do downloading of pack libraries & forge from the FTB repo
several TP related cleanups from @jikuja
refresh pack panes after packs are removed
FIXED: ModManager

 * DO not hog CPU while pack is downloading and unzipped
CHANGED: JavaFinder & Settings

 * Fixed detecting JVM which is used to start launcher under Windows
 * Added more defensive code against JavaInfo() fails.