Fix: Loading animation doesn't disappear Android

https://github.com/johndyer/mediaelement/issues/1283
Accessibility for volume control
css class for Offscreen text.
Accessibilty slider control. Fixed controls disappearing when navigating by keyboard, so when keyboard is used to focus on video the controls will appear and not disappear until focus is is moved outside video.
remove event listeners from flash AudioElement

should prevent double progress events firing from AudioElements that
have setSrc + load called twice.

refs #338
send `this` to dispatchEvent callbacks

as requested in #434
Update mep-feature-ads.js

view adsLayer only when the AdUrl is not empty, to have normal Play/Pause behaviour
Add repository field to package.json to avoid warn
Keep header comments in the minified files
Keep same order in src loader from Grunt & Builder

This just makes it easier to compare both outputs.
Fix IE8 error on window resizing
Add grunt task to build `flashmediaelement.swf`
Add task to build the CDN version of flash file
Add grunt task to clean the `local-build` folder
Remove older version of the build scripts
Update README.md

add MIT License link
Update README.md

add Pull link
Add task to remove console.log (see #1147 & #1243)

Added a new Grunt task to the build process to remove `console.log`
statements. This is important for production since, in some versions
of IE, the `console` object is only created after opening the
Developer Tools.
FIX: canplay doesn't fire correctly on Android 4.1

https://github.com/johndyer/mediaelement/issues/1305
i18n : add spanish, italian, japanese, korean and portuguese translations

Adding new translation in spanish, italian, japanese, korean and
portuguese, for all strings from mediaelement-and-player.js