Add a regression test for transparent gzip + basic auth

The bug is fixed but there wasn't an obvious test.
See report: https://code.google.com/p/android/issues/detail?id=74026
Fix formatting / parsing for Android

Ensuring that this Android bug is fixed for the next
Android release:
https://code.google.com/p/android/issues/detail?id=66135

On Android the SimpleDateFormat for "zzz" returns GMT+00:00.
This is regrettable but awkward to change as it is existing
behavior.
https://code.google.com/p/android/issues/detail?id=66136

This change fixes the format to 'GMT'.

This change also fixes a bug where the platform default
timezone was used for parsing some date/times and not GMT.

Various tests have been added to prove the behavior when
timezones are missing and dates are malformed.
Merge pull request #1011 from nfuller/FixParseFormat2

Fix formatting / parsing for Android
Merge pull request #1010 from nfuller/TransparentGzipTest

Add a regression test for transparent gzip + basic auth
Allow duplicated charsets in MediaType
Merge branch 'master' of github.com:square/okhttp

* 'master' of github.com:square/okhttp:
  Add a regression test for transparent gzip + basic auth