Update to 3.6

3.6.0.2
=======

Add hover/active states for slider assets
Fix wrong border color for primary/inline toolbar buttons
Fix wrong shadow direction in dark variant primary/inline toolbar buttons
Fix color of icons on vertical spinbuttons
Fix color of separators on toolbars
Fix unwanted shadow from menubutton dropdown

3.6.0.1
=======

Revert an erroneous commit
Use this version instead of 3.6.0

3.6.0
=====

Improve theming for sidebar scrollbars
Render PNG images for borders
Fix regression wrt. GtkScrolledWindow default background
Fix insensitive active GtkSwitch borders
Fix theming for GtkMenuToolButtons on inline toolbars
Fix Epiphany toolbar theming for RTL layouts

3.5.92
======

Adwaita:
- New improved assets for the GTK2 implementation
- Improve theming for progressbars in GtkEntry
- Improve theming for vertical spinbuttons
- Add transitions to and from GtkEntry's focused state
- Add support for theming text selection handles
- Fix GtkSpinner animation
- Fix blue border for insensitive default buttons
- Fix wrong highlight color for highlighted headings in GtkAssistant
- Drop HighContrastInverse/LowContrast GTK themes

HighContrast:
- Add new application icons
- Don't show focus ring by default
- Fix selected text theming under some circumstances
- Fix theming for the deprecated GtkStyle fallback path
- Fix GtkLevelBar theming
- Fix theming for fallback GNOME Panel