Fix merge_split_mappings( ).
Clean up set_reg_value( ).
Update try_release_token( ).
Stop checking re_evaluate regs in check_used_regs( ).
Clean up removing computations for WHNF regs.
Add some asserts.
Treat t==0 differently.
Clear relative mappings also in reclaim_used( ).
Add an assert.
Add whitespace.
Add check.
Add whitespace.
Fix try_release_token( ) for releasing the root.
Track and enforce the relative mappings.
Allow either route in merge_split_mapping( ).