This makes accounting of number of bits allocated easier. Specifically, the amount of allocated
bits is computed by doing (index->highest_bit - 1) in code.
Specifically, what this capability manager does, is map keywords to
calculated bitmasks. These bitmasks are allocated at runtime, so that
the any managed capability index can be manipulated by modules.
Modules should call capability_orphan() when orphaning capabilities. This
makes it so that bitmasks aren't reallocated, except for cases where the
capability is the same.