Error message in case file is not valid zim file
Error handling invalid/no file zimfile for all cases
Increased zoom default zoom level (Note useful for kiwix zim, writes from wikipedia are now actually too far zoomed in)
find in page added
added icon to open (but keep text); icon oder changed
Fix history issue after opening new zim file (mostly)

If zim file opened, while zim file opened before "back"
was showing a blank page.
Workaround is probably not handling all corner cases but should be good enough.
Merge branch 'master' of https://github.com/kiwix/kiwix-android.git into cip
Implemented search suggestions; Retrieve url from title; cleanup content parser url parsing

TODO: move data retrival out of UI task
TODO: message if article not available