Update zurb5-multiselect.js

Need for option update or initial selected
Makes the initial selection relies in the selected attribute too.
Updates instructions about initial values selection.
Merge remote-tracking branch 'berg/master' into initial-values

Uses :selected instead of [selected] to permit dinamically apply
multiselect and removes unwanted console.log calls.

Conflicts:
	zmultiselect/zurb5-multiselect.js
Uses the already found select instead find his options by id.

I am assuming the ID is not mandatory.
Applies the select update for any multiselect in page.

The previous code catch only one of many multiselects in the same page.
Also fixes indentation.
Merge pull request #10 from michelts/initial-values

Makes the multiselect uses the "selected" attribute of each option in the original select.
thanks man