Fixes the do not follow redirects bug

The HttpEngine would not obey the set state because there was no
correlation between the HttpURLConnection.setInstanceFollowRedirects
method and the OkHttpClient.

Fixed the missing link by adding a new setFollowRedirects method to the
OkHttpClient class.  Bridged the gap for the HttpURLConnection.setInstanceFollowRedirects
by forwarding that state into the OkHttpClient.

Now the HttpEngine will always obey the OkHttpClient redirect state when
attempting the followUp phase.

Added necessary test to both OkUrlFactoryTest and CallTest.

https://github.com/square/okhttp/issues/943
Mention correct Java version on the website.
Use HTML entity for ampersand.
Use Okio's appending sink for File.
Merge pull request #971 from square/jw/appending-sink

Use Okio's appending sink for File.
Merge pull request #970 from square/jw/java-seven

Mention correct Java version on the website.
Merge pull request #944 from MiguelLavigne/feature/mlavigne/fix_do_not_follow_redirects

Fixes the do not follow redirects bug
Move connect to be closer to connection.

This eliminates some awkwardness in OkHttpClient, where it needs
to make a bunch of internal calls to Connection.
Merge pull request #972 from square/jwilson_0628_move_connect

Move connect to be closer to connection.
Make it possible to mock OkHttpClient and Call.

Closes https://github.com/square/okhttp/issues/956
Merge pull request #973 from square/jwilson_0628_nonfinal

Make it possible to mock OkHttpClient and Call.
provide a friendlier API for multipart forms.

Also, escape the name and filename tokens, and include some small
changes from CR.
Use transport protocol in SPDY response.
HTTP/2 initial window size is 65535 not 65536.
Merge pull request #981 from square/adrian.http2-initial-window

HTTP/2 initial window size is 65535 not 65536
Merge pull request #980 from square/adrian.response-protocol

Use transport protocol in SPDY response
Merge pull request #949 from mlc/friendly_form_building

provide a friendlier API for multipart forms.
Add hpack-test-case test module.

Issue square/okhttp#931
Add trailing CRLF to multipart.
Merge pull request #987 from ChristianBecker/trailing-crlf

Add trailing CRLF to multipart.