Stackable security notes

This pull request allows people to combine security notes in to larger stacks. They can left and right click while holding the notes to combine multiple notes in to a single item and back out again.

Each time 4 notes are combined in to one of 4 times the value. This can be repeated to three levels - 4x, 16x, 64x. At the peak density, one note represents a stack of unpacked notes.

To combine notes, right click on an enchanting table with the security notes in your hand. The notes in your hand will be combined in to ones worth 4 times as much. To get the original notes back, left click on an enchanting table holding the multiplied notes. If you don't have enough inventory, you will drop the excess.

JAR is included in the pull. Testing should focus on usability, that it only works with security notes, and not being able to duplicate items. I can change the scale and/or block used to pack/unpack these if needed.