feat(theming): add theming

closes #442, thanks @skeemer
fix(styles): remove deprecated css properties

closes #450
fix(textfloat): tabbing now  works properly, css improved

Work on #469
Closes #458
chore(): update README
docs(theming): add theming documentation
fix(textfloat): added support for label/hint expressions

Updated unit tests.
Closes #462
fix(textfloat): improve ARIA pairing links between label and input.

Closes #483.
chore(): decrease docs load time

Don't include the contents for each demo's files, instead always lazily
fetch them when needed.
fix(style): fix invalid flex properties
chore(karma): make globs work with karma
test(theming): test and fix md-theme-watch
chore(): add tmp breaking file for 0.5.0
Update 0.5.0-breaking.txt
Update 0.5.0-breaking.txt
Update 0.5.0-breaking.txt
fix(md-input-group): Disable with ARIA
Update README.md
chore(build): make bower-material include themes
refactor(theming): deregister $rootScope.$watch
style(backdrop): .opaque -> .md-opaque