* startrefactoring the event system
* refactor: blockquotes, code blocks and links refactored
* refactor codeblock to new event system
* refactor subparser until ghcode to new events
* finish adating ghcodeblock to new event
* add headings to new events
* add image to event system
* add emphasisAndStrong to event system
* fix wrong event name in emphasisAndStrong onEnd event
* spanGamut and build
* showdown.helper.event refactored to showdown.Event
* partial
* add links
* add metadata
* add strikethrough and table
* build
* add underline
* add unescapeSpecialChars
* small refactoring
* remove old tables parser
* add lists
* add simple event trigger tests
* build
* fix browserstack
* fix browserstack
* remove testing for ie11 and bumped firefox min version to 45
* fixes and closes#920
* build
