Add feature: expand / collapse all results for project search scope

When I change search scope to project, there are too many files and
comments in the result panel. So, I add this feature for finding the
file and comment more easier. Now it works fine for me.
The next feature I want to add is filtering the result by tag. There are
many software which has this feature. such as Visual Studio, Eclipse.
What do you think @mikaeljorhult? Any ideas?
Use existing functions for collapsing and expanding files.
Use CSS to show and hide toolbar icons.
Remove toggleAll method as it's not used.
SVG for retina.
Add toolbar icons.
Add notes to change log.