RFC 3261-compliant Warning header

http://tools.ietf.org/html/rfc3261#section-20.43
The Warning header field is used to carry additional information
about the status of a response.  Warning header field values are sent
with responses and contain a three-digit warning code, host name, and
warning text.

The "warn-text" should be in a natural language that is most likely
to be intelligible to the human user receiving the response.

http://tools.ietf.org/html/rfc3261#page-232
Warning        =  "Warning" HCOLON warning-value *(COMMA warning-value)
warning-value  =  warn-code SP warn-agent SP warn-text
warn-code      =  3DIGIT
warn-agent     =  hostport / pseudonym
                  ;  the name or pseudonym of the server adding
                  ;  the Warning header, for use in debugging

http://tools.ietf.org/html/rfc3261#page-182
399 Miscellaneous warning: The warning text can include arbitrary
    information to be presented to a human user or logged.  A
    system receiving this warning MUST NOT take any automated
    action.
Move jshint options from Grunt to .jshintrc
Convert the remaining tabs to spaces.
Resolve all jshint errors in Gruntfile
Merge pull request #71 from CodeYellowBV/jshint

Move jshint options to .jshintrc and resolve some lint warnings
Merge pull request #69 from CodeYellowBV/warning-header-rfc3261

RFC 3261-compliant Warning header
Bump package files to 0.6.1
Remove extraneous bower instructions
Logging cleanup: Trim ICE candidate output
Logging cleanup: Check for null before method call
README.md: add npm instructions
Merge pull request #73 from seanbright/master

Logging cleanup: Trim ICE candidate output
Use Grammar to parse Content-Disposition type

This makes Content-Disposition-related behavior more correct.

fixes #6
Merge pull request #78 from joseph-onsip/parseDisposition

Use Grammar to parse Content-Disposition type
Grammar: use text() instead of input.substring(peg$currPos, offset())
SpecGrammar.js: add a couple UUID tests
Grammar: remove unused uuid_URI rule, clean up uuid rule
Grammar: fix quoted_string_clean rule

In theory, the rule returns what's between the quotes in the input.

In practice, it was slicing off the first and last characters of the input,
then returning the result. This only worked if there wasn't any SWS before
the quoted string.

Now, it actually returns what's between the quotes.
Grammar: userinfo rule uses text().slice instead of input.substring

Note that this rule is (still) broken, in that data.user gets set to a string
containing both the user and the password.
Grammar.pegjs: remove unused variable 'header' from SIP_URI rule

See 987c7e6f16f5922e635bb1f6bdd6c7c1359c012d