Better Layout - #185

1. try to compute parent layout when possible. (strench in strench)
2. node.layoutWeight => support flex-like auto-layout
3. node.wrapContent => toggle whether auto-layout should wrap content size

1. can auto resize only width
2. no strange lift when editing
3. when end editing, will request redraw. ( avoid blank text
4. if not in multiline mode, hit enter will also end editing
TODO:
when text len is 0, the edit course has been drawn wrong

2. get rid of some wraning

2. better auto resize
3. eliminate some warning