Fix bug in api.js whereby fake workers didn't load the worker code

PDFJS does not work on Windows Safari, due to the lack of support for workers passing typed arrays. At some point, the code to set up the fake worker so that things work on Safari seems to have become broken and nobody noticed - it was just calling setupFakeWorker() without actually calling loadFakeWorkerFiles(). With this patch, the PDFJS works again on Windows Safari.
Simplify get fingerprint() method
Fix hiding of the cursor in Presentation Mode in WebKit browsers
Fix css rotation for canvas and text layer.
Fix the B2G viewer and enable bot preview.
Intersect group bounding box with the current canvas dimensions.
Merge pull request #3777 from Snuffleupagus/webkitHideCursor-PresentationMode

Fix hiding of the cursor in Presentation Mode in WebKit browsers
Merge pull request #3764 from saebekassebil/fingerprint

Simplify get fingerprint() method
chrome.extension -> chrome.runtime for Ubuntu

Addresses issue #3800, where a bug specific to Ubuntu builds of Chromium
break PDF.js
https://bugs.launchpad.net/ubuntu/+source/chromium-browser/+bug/1232575
Implement initial CalGray support

Gamma and Whitepoint are supported in this patch for CalGray.
Blackpoint is not supported.
Merge pull request #3801 from Rob--W/hotfix/crx-ubuntu

chrome.extension -> chrome.runtime for Ubuntu
chrome.runtime -> chrome.extension when needed

Some Ubuntu users are still stuck at Chromium 25.
Merge pull request #3807 from Rob--W/crx-chromium-25

chrome.runtime -> chrome.extension when needed (support Chromium 20-25)
Add missing jsdocs for PDFJS globals.
Enable links beginning with 'www.' even if no protocol is specified
Inline setScale in parseScale
extract code to own method for faster JPX decoding
Merge pull request #3787 from Snuffleupagus/inline-setScale

Inline setScale in parseScale
Merge pull request #3796 from brendandahl/global-docs

Add missing jsdocs for PDFJS globals.
Minor nit fixes for api.js