Windows uv event loop fix, clr perform. api change

* dot net bridge enums were not comparing as equal if the enum was
returned from a function and compared to a constant.

* Windows uv event loop fixed to support modal dialog windows and
prevent event loop locks.

* API modified to default windows to not being visible by default

* CLR updated for performance (stores object references) rather than
retrieving the reference on each call.

Unit tests modified to reflect api changes.

** API CHANGES:
window(panel)close moved to-> destroy
window, panels, pop overs do not open by default (must set to
visible=true)