Tcaps main operations completed, but NOT tested.

Delegation, transfer, deletion, and splitting.  They are not yet
integrated with user-level scheduler code yet.

TODO:
- Add support into src/components/sched/cos_sched_base.c to the tcaps.
- Add the fountain of time that auto-replenishes the tcap root(s).
- Add proper consumption of time on timer-ticks and thread switches.
- Test tracking of budget/priority/expiration.
- Add delegation and tcap activation into the cos_switch_thread sys-call.