Set TFPATH correctly in tfrc.

The original config is incorrect in two ways:
- /set is case-sensitive
- TFLIBDIR is ignored if TFPATH is set, so TFPATH must include it.
- /eval is used to force variable expansion. Yay for TinyFugue!
Refactor tfrc to pull New Moon-specific stuff out.

Several other minor updates:
- Set histsize to 20000 and delete commented out lines to set histsize.
- Deleted a bunch of commented-out lines that aren't in use anymore.
- Split buff_tracker.tf in preparation for making it world-agnostic.