Added MaskablePixmapWidget, improved avatar rendering
ChatAreaWidget: removed frame
fix #308
MaskablePixmapWidget: fixed drawing routine
MaskablePixmapWidget: white background, removed circular mask
removed avatar_mask_circle.png from qrc
MaskablePixmapWidget: background-color argument
set default avatar to contact_dark.png, removed active/inactive avatar
switching
set profile picture to contact_dark.png
MaskablePixmapWidget: set cursor to PointingHandCursor if clickable
MaskablePixmapWidget: use KeepAspectRatioByExpanding
set clickable to true
Merge branch 'pr321'