Merge pull request #26 from aengelberg/abnf

Abnf
Altered regular expression for optional whitespace

Alex had fixed the grammar to allow for a comment at the end of the
string with no trailing newline; this is a more efficient fix,
incorporating the change directly into the regular expression.
Fixed hex digit rule

to include lower case a-f
Added test cases for abnf grammar
Added phone_uri.txt
added phone uri abnf test case
Created ABNF documentation
Documented combinator extensions
Added to documentation about ABNF
Added YourKit information
Formatting issue
Formatting issue
Added YourKit information
Added YourKit information
Formatting
Formatting
Formatting
Formatting
formatting
Added ABNF to list of features in readme