Change licence to LGPL, add licence blurb and class javadocs

Cannot really use the GPL because minecraft itself is closed source.

Added a description for each class.
Also tidied up a few comments.
Code cleanup and minor bugfixes
Change keybind from shift to grave ('~' key)
Add rotated wood to congruence list.
Add curseforge url to mcmod.info
Update version to 0.5.1