urcc compiler new version: merged source code from the front-end and the cfg/ssa/tssa code from Lingxiang Xiang
added driver code
more reorganization of the directory structure.  fixed the require path.
moved ssa pass.  added ssa driver, which calls urcc, which tests for compile method (and uses it if it is defined)
revised the opt pass calling mechanism since the driver code is in multiple files (multiple Object instances)
removed trailing commas in SSA name outputs by using collect rather than each_index
reformatted the indentation of CFG::c_ssa_dump
re-indented cfg.rb
added cs255/455 test cases
added cfg driver to output control flow graph
type class and tests
type class: added validity check, and a bug fix
type class: made constructor private, properly
add [ ] method to Type meta-class
initial code for parser, including irnode.rb and grammar_rule.rb
grammar: AltRule first test passes
nested AltRule tested
first two passed tests of SeqRule including a typed variable, created token.rb for token classes and tokenizer, my first use of meta-class inheritance
multi-line parsing tested/corrected, except for func parsing.  There is a problem of returning the next line, after finish a multi-line rule.
naming and interface improvements for grammar rule classes