#19, #20 added enum for different db systems
#19, #20 added db system enum to frontend dependencies
improved docs
added copyright header
coding style change
#19, #20 added names method to DbSystem.java
#19, #20 in ConfigurationSettingSqlIterator.java added equals and hashCode methods
added tests for getValueAsString
#19, #20 changed setValues to take a List (not ArrayList) as input
#19, #20 added DbSystem ListBox to SqlIteratorInput.java
added missing tests
#19, #20 some bug fixes in ListBoxInput.java
added missing tests
renamed getValue method
reformat
Merge branch 'master' into DbSystem-configuration

Conflicts:
	frontend/src/test/java/de/uni_potsdam/hpi/metanome/frontend/client/parameter/GwtTestListBoxParameter.java
#19, #20 added missing gwt dependencies
moved MetanomeTest gwt descriptor to tests
Merge pull request #145 from HPI-Information-Systems/DbSystem-configuration

adding db systems parameter to sql input widgets