Separate strings for bar chart statuses.
Rewrite PieChart.
Intercept scrolling events in SnappyLayout.
Disable SnappyLayout interception when scrolling in projects listview.
Deselect slices when clicking anywhere on the parent.
Merge pull request #451 from toggl/roosmaa-refactor-piechart

Refactor pie chart

Closes #420
Closes #421 
Closes #429 
Closes #440