[ComboTabBar] Fixed double clicking on scroll buttons with Qt5
[LocationBar] Tweaked Linux theme. No longer hardcode height

It is now specified only minimum height.
Fixes issue with locationbar being too small with bigger fonts.
[LocationBar] Set cursor position at start when showing long url

Also disable animations for Oxygen style, it breaks when changing
text to completely different one (eg. loading foo.com and then bar.com)
and the url is too long to fit in line
[LocationBar] Cleanup code + fixed showing rss icon
[LineEdit] Create context menu in LineEdit

Instead of code duplication in LocationBar and WebSearchBar, create
the context menu from LineEdit.
Also actually create the menu, not just re-use the standardContextMenu.
Include QDebug in qzcommon.h

It's annoying to always include it just to remove a moment after...