Facebook Android SDK 3.18.1

Summary: Facebook Android SDK 3.18.1 (see https://developers.facebook.com/docs/android/change-log-3.x/)

Test Plan: Built ZIP

Reviewers: clang, gokhanc, gen

Reviewed By: gen

Subscribers: dmmiller

Differential Revision: https://phabricator.fb.com/D1578814
Facebook Android SDK 3.19

Summary: Facebook Android SDK 3.19 (see https://developers.facebook.com/docs/android/change-log-3.x/)

Test Plan: Built ZIP

Reviewers: gokhanc, chrisp, gen, toddkrabach

Reviewed By: toddkrabach

Subscribers: subodh, dmmiller

Differential Revision: https://phabricator.fb.com/D1592127
Facebook Android SDK 3.19.1
Facebook Android SDK 3.19.1

Summary:
    see https://developers.facebook.com/android/change-log-3.x/

Upgrading:
    https://developers.facebook.com/docs/android/upgrading/
Facebook Android SDK 3.19.1
Facebook Android SDK 3.19.1

Summary:
    see https://developers.facebook.com/android/change-log-3.x/

Upgrading:
    https://developers.facebook.com/docs/android/upgrading/
Android 2.1 - Fixed NullpointerException when request timeout while dowloading image.
Android 2.1 - Fixed NullpointerException when request timeout while downloading an image.
Android 2.1 - Fixed NullpointerException when request timeout while downloading an image.
Merge pull request #391 from CristianOliveiraDaRosa/dev

Android 2.1 - Fixed NullpointerException when request timeout while downl...
Add maven central to main library

See #383 for details.
Merge pull request #393 from almozavr/patch-2

Add maven central to main library
Facebook Android SDK 3.20
Facebook Android SDK 3.20

Summary:
    see https://developers.facebook.com/android/change-log-3.x/

Upgrading:
    https://developers.facebook.com/docs/android/upgrading/
Facebook Android SDK 3.20
Facebook Android SDK 3.20

Summary:
    see https://developers.facebook.com/android/change-log-3.x/

Upgrading:
    https://developers.facebook.com/docs/android/upgrading/