CRM-14798 - Allow loading CiviCase XML files even if case-type name is malformed

For case-types registered via GUI in old (pre-4.5) versions, the
autogenerated machine names were often ucky, and there was no way to clean
them up.  We'll allow backward-compatibility in 4.5 -- and also provide
warnings/tools to facilitate cleanup.
Merge pull request #3820 from totten/master-casetype-badnames

CRM-14798 - Allow loading CiviCase XML files even if case-type name is malformed