support for mathjax
updated MathJax to 2.3, slim copy feat. MathML input, SVG output, STIX fonts
Merge pull request #34 from pkra/feature/mathjax

updated MathJax to v2.3
Merge branch 'develop' into feature/mathjax

Conflicts:
	lib/Readium.js
	readium-js
dependency update
keyboard settings tab
keyboard shortcut validation
fixed  view jumping to the top of the vew when MO player reaches next spineItem
fixed  view jumping to the top of the vew when MO player reaches next spineItem
Merge branch 'develop' into feature/continues_scroll_view_3

Conflicts:
	lib/EpubReader.js
	lib/Readium.js
	readium-js
added controls to settings dialog and hooked them to scrolling properties
submodule + build
submodule + biuld
scroll mode settings dialog: fixed typos in element names and labels, fixed HTML element nesting, added and tested accessible labels (screen readers), added i18n language resource strings.
screen readers: radio button options accessible in a cross-platform way (ugly, but works)
radio button higher contrast + icons
submodule + build
submodule + build
CSS fixes (Chrome and IE on Windows)
screen reader alerts for invalid/duplicate keyboard shortcuts (JAWS okay, VoiceOver only input text fields "invalid" message, no distinction with "duplicate")