Merge pull request #26 from pantheis/master

updates
Merge remote-tracking branch 'remotes/upstream/master'
First pass at ISidedInventory conversion. Possible problems:

Purpose of two unnamed functions is unknown; currently returning false in all cases.
Arrangement of block side indexes needs verification.

Down to 21 errors, all texture related.
Block and Item texture code redo. Slots not done yet.
GUI texture references should be fixed now. That was easy.
Missed a spot!
Slot icon code done, for now.

This could probably be better. Having them registered by some particular
item makes no sense, but there appears to be no other way to do it
currently.
Texture file unstitching
IC2 API update
First round of bugfixes + code cleanup + method research
Merge pull request #109 from Tallinu/master

APM runs, seemingly stable, but still has bugs in the container/GUI code at least.