Remove some addressed FIXME notes
Switch to test-framework instead of tasty
Test case with a simple loop
Fix an SSA labelling bug with argument labels

Arguments were being introduced into the value number mapping too
soon (formerly before labelling started).  This prevented the recursive
registerRead function from being called.  In cases where the entry block
had predecessors that assigned to the same register as an argument, this
overwrite was not detected.
Interim checkin of bug fixes to the SSA labeller

This follows the algorithm in the paper more closely, incorporating
the notion of filled and sealed blocks.  These are criticial for dealing
with intialization.  Also, this adds some bookkeeping phi nodes in the
entry block to stand in for arguments.  These are necessary when dealing
with loops (especially when the arguments aren't read in the entry).
Split the BasicBlock abstraction into a separate module

It isn't very re-usable, but the split declutters the main
labelling code.
Add a new test case

This is the test case that p6 was supposed to be, but
p6 had a funny typo (it is still a good test case).
Removing debugging spew
Remove some obsolete fixmes