changes signature of event listeners and moves the list of event names from class instances to 'static' class property
adds error code to error object in SourceBufferExtensions append/remove events
Merge pull request #315 from MSOpenTech/development

changes signature of event listeners and moves the list of event names f...
fixes "Unable to get property 'getCurrentTime' of undefined or null reference" exception when switching mpds
fixes seekTarget detection in PlaybackTimeRule
fixes jshint errors
updates dash.all.js and dash.min.js
Merge pull request #322 from MSOpenTech/development

Bugfixing
Extended DRM support

* Adding Widevine support.
* Extending PlayReady support with optional CustomData.
* Adding option to override protectionData (including laUrl, cdmData &
license request headers) when instantiating the player.
* Moved parsing of CDM message into respective DRM license acquirers.
* Merged changes by @colde.