Added immediate click to drag

Added a feature where you can immediately click and drag an object
without it being selected.
No selection click drag fix

Added code so that we can't accidentally click on manipulators other
than translate.
Removed weak references from msg sys

This was an experiment that really wasn't needed.
Snap settings display cleanup
Start of adding notify property change to settings.
That was painful

There has to be a better way. Maybe improve GOAT to generate classes
like this for us. It's a perfect case for code generation if we can
extend the code gen to have better default values and support for min /
max clamping.
Removing reactive
Immediate translate fixes

* Only allow operation with no keyboard modifiers.

* Removed code code that wasn't needed. We were tracking if we should or
shouldn't handle a mouse message after we started dragging. If we
started a drag we should always eat the end message because the act of
starting a drag took input control.
If we hit any selected entity don't do anything.
Bug fixes for no selection drag

* Fixed collision issue giving false positives for the translate handle
test.
* Only allow no selection drag if we don't have a hover handle.