Use unsigned int where warranted
Introduce ROOT::ClassTableHash
Migrate TClassRec to implementation file (hide implementation detail)
Add proper constructor to TClassRec
Add proper destructor to TClassRec (fix memory leak)
Add helper class TClassAlt
Add TClassTable::Check and TClassTable::AddAlternate
Add verbose and debug ACLiC option;

This allows to issue the ACLiC internal information message without setting gDebug
(which is nowadays way to noisy when set to 7) or to 'just' keep the output files
(option 'd' for internal debugging).
Provide ROOT::AddClassAlternate.

This is for the dictionary to be able to access TClassTable::AddAlternate without having
to include TClassTable.h (see ROOT::AddClass)
Register the requested as an alternate to the normalized name
Use TClassTable::Check in TClingLookupHelper__ExistingTypeCheck