Guard against null activity and arguments
DRY up how file is opened in new activity
Use application/xml mode for '.xib' files
Use default protocol and host when missing

This prevents the app from crashing when a link's
Uri has only a path that starts with '/' in it.
Ensure data URI always has non-empty scheme and host

Use https://github.com when missing for relative
links.
Add missing override annotation
Remove image getter before adapters and tasks

Previously a new image getter was created for the adapter
which would cause comment text to not update when refreshed
if it had been edited.
Update Ukrainian translation

Closes pull request #225
Add Traditional Chinese translation

Closes pull request #228
Add Bulgarian translation

Closes pull request #233
Remove trailing whitespace
Use ellipsis character in loading_followers string
Add support for sharing a Gist
Use subject as description when present
Create helpers to get body/subject from share intent
Add support for sharing an issue
Add support for sharing a viewed commit
Add missing override annotation
Use externalized string for initial title
Add support for sharing files