Learned to fork.

Corrected register init by adding initialization of registers pass after lowering. Finished expand-whens. Needs more thorough testing of instances

Finished first two parts of expand-whens pass. Fixed inits by adding WRegInit and removing Null and initialize-register pass

Finished expand accessors pass. Fixed bug in resolve-gender. Added tests, all pass. Minimal removal of letrec to get WritePort to work correctly - a more thorough removeal is still needed

This reverts commit cce4364f.

Added debug print statements to dump fields from nodes, and updated tests to call firrtl correctly to enable/disable them