Comic plasmoid progress

[Reza Shah]

Hi,

I have pushed some changes for comic plasmoid at rshah/comicqml.
Basically i just move some UI parts to QML side, and left the logic as
current(hopefully)

As i'm never use this plasmoid before, i'm not sure if some bugs
introduced in this porting exist previously or new bugs.

There are some issues i'm aware off, and need some inputs:
- i'm not using(not ported yet) ImageWidget class, i just use normal
QImageItem (not sure if we really need scrollbars as implemented in
ImageWidget)
- not sure how to port the ability to change plasmoid size after comic
strips loaded (ComicApplet::updateSize()).
- 'Actual Size' action not implemented, related to ImageWidget.
- The cursor for comic identifier and comic url label not changed to
pointing hand
- Not sure if ComicTabbar (qml) should be exposed to C++ side or not.
- The buttons(prev,next,zoom) in ButtonBar, will not be highlighted on
mouse hover

As i'm new to QML things, i believe there are many things not quite
right in my implementation.

Please try and share some thoughts.

Regards,
Reza