Fix bug: AUTO:WEAPONPROF with PREWEAPONPROF throwing stack overflow
* Reject an attempted loop at parsing time.
Issue#: CODE-2251


git-svn-id: svn+ssh://svn.code.sf.net/p/pcgen/code/Trunk@21319 ef53c05b-3124-4d59-ae7d-fe3273f42be7