Fix SD Polyfill + document.baseURI

I assumed (incorrectly) that SD Polyfill provided wrappers for document.baseURI
factoring and comments.
Force UTF-8 charset for imports to be spec compliant

Fixes #50
Merge pull request #51 from azakus/utf8

Force UTF-8 charset for imports to be spec compliant
README: add WebComponentsReady
Process scripts more normally: scripts are simply injected into the main document and run rather than loaded via xhr.
This should make the polyfill more csp compliant. Specifically, external scripts will be loaded as external scripts rather than being xhr'd and eval'd.
Merge branch 'official/master'

Conflicts:
	src/Observer.js