Make Flame.View's position configurable

[ctimmerm]

Currently we can control the view's position by setting useAbsolutePosition.
Let's change it so that we can set the position itself and use the layout based on that.

[guilhermeaiolfi]

Currently I'm using a modified version of LayoutSupport, where I changed a line in _renderElementAttributes from:

if (!this.get('useAbsolutePosition')) { return; }

to

if (!this.get('useAbsolutePosition')) { buffer.style('position', 'relative'); }

And everything started to work when using useAbsolutePosition=false.

[guilhermeaiolfi]

Have anything changed in this regard? Using widgets relative to the page seems a pretty compelling feature.