Eliminate PlayerCharacter.canSelectAbility (since it was mostly redundant anyway - only unique part was prereq test)
Other minor related cleanup

Issue#: CODE-2465


git-svn-id: svn+ssh://svn.code.sf.net/p/pcgen/code/Trunk@23458 ef53c05b-3124-4d59-ae7d-fe3273f42be7