Merge pull request #233 from rgagnon24/master

Add 'scroll' event, use Dynamic width of container
code style; update build
containerWidth -> wrapper.clientWidth
resolves #250 (broken download link)
marks, selections, regions -> regions plugin
region events
loop region
regions api
update major version; breaks marks, selections and regions APIs; introduces new Regions API
Merge pull request #253 from katspaugh/regions

Regions replaces Mark, Selection. Refactored into a plugin.
update index
rm mediaelement backend and loadStream
resolves #252: replay after finish
add drag selection to regions plugin
bump version
region handlers
region loop
bump version
Update wavesurfer.js
Merge pull request #257 from sorensenjs/patch-1

Sets correct value in skipBackwards