QML widget explorer

[Marco Martin]

Hi all,

After almost a year of stopped development, I think the qml rewrite of the 
widget explorer and activity manager are almost ready for merge :D

there are still some layout/behaviour annoyances especially on vertical 
panels, but should all be easy fix.
(biggest annoyance is that the mouse wheel doesn't work in horizontal mode and 
is probably a problem of Flickable, so it could need a new c++ binding just 
for the mouse wheel :/)


apart from that, aestetically is much better, is smooth, fast and the diff is
+1887 lines of mostly qml
-4617 lines of mostly c++

ease of maintainace ftw ;)

the branch is plasma/mart/declarativeWidgetsExplorer

if nobody complains i'll merge it in master shortly (tm)

Cheers,
Marco Martin