Refactored add/show/hide/removeFromDom methods
redefined add/show/hide/removeFromDom

so that it can be called used by the dismiss button and have optional
parameters
Implemented specified behaviour for persistant toast

Now the "flushing" of the toaster is not only triggered when it's
completely empty but also when it all non persistant messaeges have
expired.
Replaced link for animate.css with CDN
Fixed a bug when persistants are dimissed
deleted style.css
Merge branch 'ToasterPersistantPbSolved' into Toaster

Conflicts:
	Toaster/style.css
Added option to invert message insertion in toaster
renamed placement attribute to placementClass