Merge pull request #25 from piotr-ruchwa/master

UnityAds adapter version 2.2.0 (UnityAds SDK 1.3.8)
[134943215] preparing facebook update beta release
Merge pull request #26 from hkosacki/update_facebook_3.19.1_134943215

[134943215] preparing facebook update beta release
[139336550] removed jars from beta - they are moved to mobile-sdk repo
[139336550] fixed placement ID for facebook
Merge pull request #27 from hkosacki/promote_adcolony_to_prod_139336550

[139336550] Release AdColony as stable
Update Readme to introduce Beta program
Update Facebook adapter to 2.0.1 (Facebook SDK 3.20)
Merge pull request #28 from fyber-lima/update_facebook_int_3.20_134944997

Update Facebook adapter to 2.0.1 (Facebook SDK 3.20)
Facebook - drop support for iOS 5 and iOS 6
Merge pull request #29 from fyber-lima/update_facebook_int_3.20_134944997

Facebook - drop support for iOS 5 and iOS 6
Create Tremor adapter 2.0.0