Adjust the size of the elements in the statusbar

Use the same height for all the elements and try to prevent
variations of the speed labels.
Show current speed limits in the status bar

Closes #1316.
Merge pull request #2061 from pmzqla/speed-indicators

Show current speed limits in the status bar
Resize and crop the icons used in the status bar.
Let Qt decide the size of the statusbar.
Enable backtrace support for mingw builds too.
WINDOWS: Fix automatic python download. Commit 0799dc2 broke this. Closes #2076.
Fix menu width
Fix context menu width
Set images cache expiry time to 300000 seconds
Add "Speed in title bar" item to menu

* file: src/Icons/oxygen/checked.png
  copyright: Victor Buinsky <allok.victor@gmail.com>
Use localStorage instead of cookies
Fix the language selection in the combobox when the system locale only has a lang equivalent and not a lang_COUNTRY one. Closes #1786.
Merge pull request #2201 from buinsky/master

WebUI: Some changes