Add data type manager
remove missing empty class
Add Scope preference page and data types refatoring
Merge branch 'master' of https://github.com/aradouan/ReqCycle into Branch_master_typeManagement
rename package (impl.internal to internal)
Add Scope and types configuration pages on the preferences
Merge branch 'master' of https://github.com/aradouan/ReqCycle into Branch_master_typeManagement