Update TweetListView.qml

scrollToBottom is buggy at long dyncamic listViews, but positionViewAtEnd work flawlessly.
Update TweetPage.qml

Autoscroll to bottom when ancestorRepeater items loaded
Merge pull request #142 from CODeRUS/patch-1

Update TweetListView.qml
Merge pull request #143 from CODeRUS/patch-2

Update TweetPage.qml
show retweet and favorite count if known