Corrected comment spelling, removed print_r statements in tests
Added test for implied dt-end case with full ISO8601 dt-start
Added Mf2\fetch()

Closes #41. This update introduces a new top-level function, Mf2\fetch(), which fetches a URL and returns the parsed microformats if the content was HTML, optionally converting
classic microformats, and putting cURL’s info associated with the request in a separate variable for debugging.

Also added a minimal test which hits the network to test a successful example and a failing example.
Merge branch 'master' of github.com:indieweb/php-mf2