changed ViewRegistrations to use a HashMap for easy lookup of a ViewRegistration
object based on a ViewId
Added the HashMap also for the ViewDescriptions, now used everywhere and no ordering
needs to be assumed.

Removed unnecessary test output in XmlIoViewRegistrations.java

Merge branch 'master' of github.com:tpietzsch/spimdata

Conflicts:
	src/main/java/mpicbg/spim/data/registration/XmlIoViewRegistrations.java