remove drag helper

this did not provide enough control to handle the various use cases
remove geometry properties from Item
add a generic geometry handler class
remove the Widget class

it's more flexible to use a geometry handler for items which need to be
procedurally layed out
add @class doc tag
add title bar button PNGs
add a simple button class
Add a public ResizeGrip class
remove utils file

i dont know why i keep adding it...
add parent-child support to Item

this also adds automatically-destroyed signals
update Button to use new Item features
wip