Update README.txt

Removed spaces from the grun alias so copy and paste people will not get an error.
Merge pull request #149 from abrown28/master

Removed extraneous spaces from the alias grun command
don't call process() if args aren't specified
added Dave Parfitt to contributors.txt
Merge pull request #151 from metadave/dip_check_args

don't call process() if args aren't specified
Additional IntervalSet unit test (catches underlying cause of #153)
Fix IntervalSet.add when multiple merges are required
rm bad comment.
Remove unnecessary method Utils.replace (already exists as String.replace)
Pair and Triple are immutable, and Triple is not a Pair
Add a non-null default source Pair for CommonToken
Clarify type widening casts
Simplify LEXER_CHAR_SET rule
Do not allow raw newline characters in a lexer char set
Do not allow raw newline characters in lexer string literals
add TODOs and fix a -1 to be a constant.
Use lexer commands instead of actions where available
Use accessor methods for CodeGenerator.templates and CodeGenerator.target
Remove unused Target methods
Separate visibility and "bad word" analysis in Target