Preliminary implementation of Audio Player support for Desktop Browsers.
Two types of Players are introduced:
- MobileAudioPlayer was left without changes and has mobile-related tricks for initialization
- DesktopAudioPlayer uses streamlined approach for initialization
Adding public API for MediaOverlay, minor fixes
Merge trunk branch
Merge branch 'trunk' into feature/mo_browsers
Fixed handling of SVG Content Documents.
 - _$epubHtml is loaded with <svg> element if no <html> element is found.
 - _meta_size is loaded from <svg> element's width & height attributes if necessary.
Bugfix-33 Allow elements to have a period in IDs.
Merge branch 'develop' of https://github.com/readium/readium-shared-js into develop

* 'develop' of https://github.com/readium/readium-shared-js:
  Bugfix-33 Allow elements to have a period in IDs.
Merge pull request #6 from irls/feature/mo_browsers

Preliminary implementation of Audio Player support for Desktop Browsers.
cleanup
fixing Media Overlay player (OSX was broken)
removed incorrect MO API
ReadiumJS detection (to be fixed)
oops, typo! :(
forcing use of regular audio player (works on Firefox, Chrome, Safari on OSX)...needs testing on other platforms