LayoutChild initializers
Added align_vertical and align_horizontal layout methods for simple children placement
LayoutChildren grouping
Added Layout add_children method
Provide LayoutChildren with properties that affect children
super via the actual names of the parent class
Provider setters for height and width for layoutchildren
Handle missing children for height of layoutchildren
Return LayoutChild if layoutchild is passed into itself
Move align functions to LayoutChildren
Layout optimize
Remove LayoutChildren and make it plain Layout