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
README.md: add npm instructions
src/EventEmitter.js: inherit from Node's EventEmitter
src/EventEmitter.js: implement event initialization/validation
src/SIP.js: require EventEmitter correctly
src/EventEmitter.js: don't init _validEvents in constructor

Since the constructor might not be called when EventEmitter is extended,
methods should work if _validEvents is undefined.
src/EventEmitter.js: implement checkListener

also rename filterMethod to filterFluentMethod
test/spec/SpecEventEmitter.js: try not to modify internals when testing
test/spec/SpecEventEmitter.js: remove bad anti-method tests
src/EventEmitter.js: filter the 'on' method
src/EventEmitter.js: .initEvents() clears existing events/listeners
test/spec/SpecEventEmitter.js: call .initEvents() before .on()
test/spec/SpecEventEmitter.js: fix 'only accepts functions' test