Merge pull request #352 from R4md4c/release

Implementing ViewHolder pattern inside TweetFeedListAdapter and DirectMessageConversationListAdapter
Update change log and go back to Beta 2 for late feature by @R4md4c
Solved a bug that happens when reused cell preserve its display avatar image when download images setting is set to false
instead of displaying the anonymous contact picture.
Storing references of TweetFeedItemView views in a ViewHolder instead of using findViewById each time the cell is reused.