Fix regressive starting crash with 'showTrayIcon=false' settings parameter

(backported from 1.x branch)
Fix wrong 'imgur' uploading result string for bb-code with preview

(backported from 1.x branch)
Add AUTHORS list
Bump version number to 2.0-dev
Fix some smapp typos in README
Merge pull request #59 from QtDesktop/master

Merge fixes backported from 1.x branch