feat(IResponse): add interface to enforce basic response types
feat(IRequest): add basic interface for Request
chore(package.json): update traceur-compiler to v0.0.45

Karma was having issues with the older release
chore(karma.conf.js): slight adjustments to files loaded and preprocessed

These adjustments match working patterns from watchtower.js and other v2 repos, and are
working in my local tests.
chore(gulpfile.js): add task for running tests (`gulp test`)

It's more fun to just say "gulp test" instead of the whole "karma start <config> ..." thing.

Closes #17
fix(ConnectionMock.spec.js): monkey-patch with PromiseMock for these tests

Previously, tests were failing due to depending half on patched code, and half on native promises
which did not interact with the mocks as expected. Calling PromiseBackend.patchWithMock() before
each test, and restoring the native promise after each test, corrects this behaviour. Ideally,
this should occur for all test files, but for now the problem is limited to ConnectionMock.spec.js.

Closes #18
Closes #19
feat(jsonp): implement basic JSONP transport