Partial merge to 2.6.2rc1 : Merge commit '2b50f30' into next

Commit 2b50f30 simplified and fixed bugs in code that had already been
modified extensively by 4da88fb and 6b1dd81. This merge resolution
commit is a manual replay of the changes from 2b50f30 onto next.

Manually Resolved Conflicts:

lib/puppet/parser/type_loader.rb
spec/unit/parser/type_loader_spec.rb