Added expand/collapse all and restyled diff boxes

fixes #388
Positioned collapse/expand all button.
Updated CHANGELOG
Simplify intelligent date mode
Various UI tweaks for the History feature.
Merge pull request #405 from SAPlayer/history-time

Simplify intelligent date mode
debug feature documentation
do not trigger events when changed file is outside the current project (#397)
fixed some event handling
nit debug mode
history viewer now has close button (fix #401)
fix view authors of selection when selection ends on the beggining of the line (fix #398)
Merge remote-tracking branch 'FezVrasta/expandCollapseAll'
fix some history viewer bugs
Version 0.13.2
Updated based on feedback.
Forgot to align this properly.
Merging.
Tweaks and made expand/collapse icon match expand/collapse text.
Subtler shadow.