Redirect SparkPolymer.initLookAndFeel() to super.*
Reduced inclusions of Bootstrap to bare minumum + eliminated some dead code

initPolymer takes ~1.2-1.7 seconds now vs. ~1.8-2.2 before.
onReady arrives in ~120-180ms vs. ~250ms before.
Use minified bootstrap.min.css
Merge pull request #1433 from ussuri/minimize-bootstrap-usage

Minimize bootstrap usage