use generic method for Enum value creation
refactor data model,
rename package from "org.eclipse.reqcycle.repository.requirement.data" to "org.eclipse.reqcycle.repository.data"
missing files
remove useless lines of code + fix comment
Merge pull request #2 from MatMaul/master

remove useless lines of code + fix comment
Huge refactor, the relationships are now managed through the TType
class.
A plugin has the possibility to make its relation public.
Using this information the configuration can now display traceability
according to this information
modifications : CORE + UI
Merge branch 'develop'
Fix bug with traceability view
enhance relation based type to keep trace to original type
Cache the data of the type checker.
Each time a type is computed, the data is saved in a cache 
in case of a new build the cache for the building resource is
reinitialized. Performance are now acceptable for type management