Merge pull request #8 from erwinwinder/master

Model and ui changes
Merge pull request #10 from erwinwinder/master

Added lookup lists
correct copy/paste error
correct genomebrowser error in data explorer
Merge pull request #11 from bartcharbon/master

correct copy/paste error
Move persistence.xml, index PalgaSample
Merge pull request #12 from dennishendriksen/master

Move persistence.xml, index PalgaSample
Added retrievalterm importer
Made fields nillable
Lookuplists and hide annotators
Thesaurus and retrievalterm importers
Removed commented code
Optimalizations