Intelligently determine which iso8601 time format to parse with.

Leaving other methods in place as to not break backwards compatibility.
Merge pull request #435 from rubymotion/intelligent-iso8601

Intelligently determine which iso8601 time format to parse with.
Remove reference to BW::HTTP in the Readme

Since we don't want people using this anymore.
Merge branch 'master' into http-require

* master:
  Remove reference to BW::HTTP in the Readme
  Intelligently determine which iso8601 time format to parse with.
Don't make the requirement spec depend on http
Completely deprecate BW::HTTP