Beginnings of the new compiler

WIP: Intermediate representation (IR) data structures and conversion
Fix IR conversion
IR Cursors
Fix recursive conditional
Some typos in comments
Coalesce nodes after IR manipulation
Remove test code
IR Translator: PROGN
Remove duplicated progn
Simplifications, better comments and BLOCK/RETURN-FROM IR translators
Merge branch 'master' into new-compiler
TAGBODY and GO translators
Fix ir-complete
Correct `ir-convert' comment
Fix block
Incorrect funcall IR conversion for testing
Primitive call nodes
typo
Fix TAGBODY
Basic FUNCTION IR Converter