Fix encoding

Partly cherry-pick commit miicha/tabutils@ec86cf06a9b1bfe3001e64bea41eac1ed67a8765

Conflicts:
	chrome/content/tabutils.js
Translate some comments

Cherry-pick commit miicha/tabutils@96f712a1d6bf6fe7f2e27bc5669f4edd393b43a4