adds support for Pixate and NUI, and adds style_classes but doesn't implement it
ahh, so *that's* why it uses instance_exec...
to avoid the instance_exec class-renaming thing, you can accept an argument in this block
styling style_classes (the simplest way)
refactored 'layout' method to accept stylename, style_classes, and styles
changed setTranslatesAutoresizingMaskIntoConstraints to check target and relative_to
fixes the autoresizing thing - worried about this, though... and caches according to orientation, does not use device orientation
testing 'first' doesn't mean anything, i'm calling it 'main', which means just as much i suppose...
importing a stylesheet imports its instance variables, too
adds UIAppearance stylesheet to teacup!  and styles applied using `subview` and `layout` are reapplied in `restyle!`
subview and layout now accept 'real' styles (e.g. orientation-specific styling)
fixes to applying handlers to UIAppearance, but uncovered a bug when using `when_contained_in`
fix inspect and added some comments
fixes to UIAppearance so that 'when_contained_in' settings are kept separate
changes to stylesheet extensions and specs
like they say: the more changes, the smaller the commit message

j/k.  added everything I promise in README2.md:
UIAppearance,
some behavior changes,
refactored stylesheet extensions,
moved MotionLayout support into Layout module
added stylesheet class method to Layout (via LayoutClass)
did I mention that README2 is 1000+ lines? :-|
don't need both READMEs
some changes based on my read-through
Update README.md

Fix some typos
changing 'h1/h2' markdown syntax now that i've got the structure decided