Fix systray icons in Windows 8 camouflage

None of the icons used in the systray looks like something from windows (ignoring the size, see #7316 (closed)), and many of them contrast sharply against the blue theme.

The systray icons should be changed to ones from Windows that makes sense, either esthetically (e.g. Florence could have the keyboard icon which I think correspond to keyboard layout settings, not an on screen keyboard) or functionally (e.g. nm-applet could have Windows’ networking applet’s icon).

Feature Branch: bugfix/7326-systray-icons

Parent Task: #6342 (closed)

Original created by @anonym on 7326 (Redmine)