! Added (rough draft) 2.0 support. Still missing some small / rare things.
+ Fixed rake to < 10, because 10's file dependency handling is so very broken.
+ Added compare20 rake task to diff the grammar architecture against MRI.
+ Switched `rake debug` to default to 2.0.
- Switched ruby_parse_extract_error to use binread.
- Fixed BEGIN {} to return a sexp.
- Fixed op_asgn nodes to #to_sym their args properly.
- Fixed block_command and block_call (eg a.b c d) to #to_sym their args properly.
- Fixed assoc args in 1.9.
- Cleaned up a LOT of arg handling (block and defn, not calls) by using #args.
- Fixed optional value block args.
- Fixed support for empty symbol (wtf?).
- Lexer is now declared UTF-8 internally. Hopefully this will fix the encoding mess.
- Extended IDENT_CHAR_RE on 1.9+ to top out at \u{10ffff}... because we NEED a million unicode chars.
- ESC_RE is set to unicode. This seems problematic. *shrug*
- Switched a number of lexical constructs to use IDENT_CHAR_RE instead of \w. I wish there were something cleaner for regexps + unicode.
+ Added %i(symbol-names...) support. (%I too)
- Apparently ruby doesn't warn for escaped octal that goes above 7. wtf.
- RubyLexer#unescape ignores bad octal/hex and returns unicode strings.
- Fixed arg_blk_pass to allow for sub-args nodes.
+ Added shadow nodes for scoped block args.
- Fixed assignable to allow for sexps to be passed to it.
- Made UTF_8 the default guess on encodings when it isn't explicit.
+ Added 140 more tests, jumping test count from 1376 to 2143. Yay for test reuse!

[git-p4: depot-paths = "//src/ruby_parser/dev/": change = 8669]