Actual Memory address

Get memory address given a tracker unit.
Mark used pages

Begin marking pages as used. First step to awesomeness..
Bug Fixes + Deallocation

- Fixed bug with marking pages used.
- Added deallocation logic, so now we can successfully deallocate
memory(hopefully)

TODO : Found a bug in allocation : When the first tracker unit has less
than the requested pages in FIRST_FIT, it will use what's remaining,
but when the unit has more, it wastes pages. Need to fix this case.
Hopefully not a large change.