some error messages are now emphasized
added option to delete Phd Guidance Documents
Merge pull request #580 from cbartol/ticket/rt#422187

Corrected the style of some error messages, some error messages are now emphasized
Merge pull request #579 from cbartol/ticket/rt#404219

Added option for Phd Coordinators to delete Phd Guidance Documents
close #578
Bug fix: exceptions were being silently encapsulated and leaving
inconsistent data
Minor change: allow to create a registration with no learning agreement
as long as the agreement only requires the degree to be chosen
Refactor RegistrationAgreement to repalce it with RegistrationProtocol. Removed all possible references and uses of RegistrationAgreement. Added Alien RegistrationAgreement type.