Merge pull request #312 from beriain/development

Some corrections
version bump to 0.5
Update German translation.
Merge pull request #313 from suraia/translation-de

Update German translation
Merge branch 'development' of github.com:siacs/Conversations into development
Update Dutch translations.
Merge pull request #315 from jelmer/dutch

Update Dutch translations.
Merge branch 'development' of github.com:siacs/Conversations into development
added swedish translation by @andersruneson
fixed npe when user was very quick with starting to type in startConversationactivity
fixed npe with unsuccesfull bind
migrated some ArrayLists to CopyOnWriteArrayLists
fixe race conditons with newIntent
trying to work around npe in androids xml parser
updated readme a bit
fixed bug in message parser
line break for readme
added more features to readme
bumped to version 0.5.1
added changelog