Fix ROOT-6316: autoload triggered by names as specified in xml/linkdef

we now add to the rootmap files not only the normalised name of the
classes, but also, if different, the name with which the user specified
them in the linkdef/selection xml.
Respect the choice of the user not to use the classname as autoload entry.

therefore do not put in the rootmap the normalised name but also the
name as specified in the selection.
Register templates as if they were classes.

(cherry picked from commit addff777d3365d45197acad0a9d0e5150d30560e)
After calling the dict function we must call PostLoadCheck
If the class is unknown, parse the template and try again.

(cherry picked from commit 2665fa23011c77c1653096637a79c1e9967b6480)
Don't autoload/autoparse during RegisterModule
Make sure the autoparse search again for symbol after a new module/library is loaded
Detect payload code also for template
Make sure to use the correct ClassDef when autoparsing
Do delete the STL dict's rootmap during configure.

No longer delete those rootmap files as they have been for a while back to be usefull in v6.
Correctly handle the directory part of the library in the multiDict support
Correctly generate the rootpcm and rootmap during the GenVector32 dictionary generation.
Correctly generate the rootpcm and rootmap during the SMatrix32 dictionary generation.
Do not deserialize all nested decls but rely on HandleTagDeclDef.
Add Anders and his TTreeReader.
Return success for AutoParse()!
Fix ROOT-6322: avoid adding empty autoload keys to the rootmaps

The fix is trivial: check that the requested name is not empty.
Indeed an empty requested name is a "" and not a nullptr.
Fix test.
fix a warning
Fix warnings