Remove the remove saved search long press dialog in TrendsPage
Harmattan: add postrm to remove database & thumbnails after uninstalled
Fix some bugs in DM

* DirectMessage.insertDM() function use "newer" type instead of using
reloadType, which may not be "newer"
* When a DM delete response received from streaming, it will be remove
from DMThreadPage as well
* When new DM received and in DMThreadPage, that thread will not marked
as unread
* Correct some spelling error in UserStream.js
Coding improvement

* Cache.qml: Add/improve storeHashtags() and storeScreenNames()
functions
* DirectMessge.qml & TweetListView.qml: Improve refresh() and
onParseComplete() functions
* NearbyTweetsPage.qml, TweetSearchColumn.qml & UserSearchColumn.qml:
Improve refresh() functions
Merge branch 'master' of https://github.com/dicksonleong/Tweetian