Remove old -moz prefixed rules from viewer.css
Takes SMask's preblending in account
Remove caching of stream data and fix object loader for streams.
Bug 879161 - Fix pdf.js mimetype check.
Merge pull request #3450 from brendandahl/fix-mimetype-check

Bug 879161 - Fix pdf.js mimetype check.
Merge pull request #3441 from brendandahl/less-cache

Remove caching of stream data and fix object loader for streams.
Merge pull request #3406 from Snuffleupagus/remove-old-moz-prefixes

Remove old -moz prefixed rules from viewer.css
Merge pull request #3439 from yurydelendik/smask-preblend

Takes SMask's preblending in account
Download PDF from cache for non-Firefox add-on

This feature relies on URL.createObjectURL, which is supported by
- Firefox 4
- Chrome 8
- Opera 15
- Internet Explorer 10

If the feature is missing, it falls back to downloading from the server.

The environment-specific code are put in ifdef's. Two methods are
defined:
- noData
  This function is used as a fallback in case of failure, it triggers
  a download directly from the server.
- triggerSaveAs(String url, optional String blob)
  This function attempts to show a Save As dialog for a given URL.
  It attempts to use the a.download attribute, if available, and
  falls back to window.open(<url>, '_parent') if unavailable.

See also http://caniuse.com/download
Put URL = URL || webkitURL in compatibility.js

Declares the URL variable globally. If the feature is not
supported, the variable will still be declared, but have the
"undefined" value.

Supported by:

- Firefox 4
  Firefox 21 in Web worker

- Chrome 8  (prefixed as webkitURL), 23+ unprefixed
  Chrome 10 (prefixed as webkitURL) in Web Worker, 23+ unprefixed

- Opera 15
  Opera 15 in Web Worker

- Internet Explorer 10
  Internet Explorer 11 in Web Worker

- Safari 6 (prefixed as webkitURL)
  Safari 6 (prefixed as webkitURL) in Web Worker