Using boostrap icons for staging operations.
Merge remote-tracking branch 'upstream/master'
Using observable for adding/removing class
Merge remote-tracking branch 'upstream/master'

Conflicts:
	public/templates/staging.html
Added stash button.

Not sure if paper clip is the best one.  But a lot of the buttons are missing and bootstrap might need upgrade.
Merge pull request #263 from codingtwinky/master

Using boostrap icons for staging operations.
Invert toggle all graphics

To follow the checkmarks next to the files
Temporary progress bar helper template
Make sure git results are strings
Always show refresh-button for staging
Add CONTRIBUTING.md file with better contribution documentation. Fixes #258
Allow slash in remote ref names. Fixes #271