Porting okhttp3 integration to Glide 3

[frindly]

I ported the okhttp3 integration to the Glide 3 branch, see #856

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[frindly]

I signed the CLA.

[TWiStErRob]

Awesome, lgtm.

Reminder: #257 will need a re-fix for this as well.

[TWiStErRob]

Oh and I opened #888 because the version looks weird compared to the v4 okhttp3 one. @frindly you needn't worry about this.

[frindly]

Thanks -- I couldn't really tell what the version strategy was, so I tried to be consistent with what was in the other integrations.

[TWiStErRob]

Yes, you did good. The current idea is that all integration libs have the same version, separate from the main lib's version (this might change with 4.0). I tried to make it more obvious by removing duplication, but it didn't work, resulting in GRADLE-3380.

[sjudd]

LGTM, thanks! Would you mind squashing your commits? If not I'll get to it soon.

[frindly]

squashed

[sjudd]

Awesome thanks!

[TWiStErRob]

@frindly you may be interested in #897

[frindly]

Of course -- they upgrade off RC one day later. I'll look at updating it next week.

[b95505017]

Glide 3 using sync call with OkHttp without callback, so I think it could upgrade the version directly.

[b95505017]

Would you mind publish a new stable release for Glide 3 with OkHttp 3.0 integration?

[TWiStErRob]

I think we missed this, see #941
Library module in v3 is not published, everything there depends on :glide as far as I remember.