See "Case-insensitive language comparisons per RFC 4646"
https://github.com/fabi1cazenave/webL10n/pull/51
Removed the "patch" in compatibility.js and fixed the bug in webL10n,
because the logic belongs to webL10n instead of PDF.js.
The immediate motivation for this patch is that Chrome 40 converts
navigator.language to lower case: https://crbug.com/454331
Based on http://pastebin.mozilla.org/3061694
1. Remove "debug helpers" and use console.log/console.warn directly (top).
2. Remove page load initialization (middle).
3. Remove window._ alias (bottom)
The original diff contained an extra entry
"Adds fallback argument to the getL10nData;",
but this was already implemented in the rebased webL10n, so it's no
longer PDF.js-specific.
