-Have dhcp plugin reuse omapi key if already stored
-Allow preprocessing functions to callback just like processing functions
-tabedit accepts/prefors 'TABEDITOR' variable, defaults to vi
git-svn-id: https://svn.code.sf.net/p/xcat/code/xcat-core/trunk@329 8638fb3e-16cb-4fca-ae20-7b5d299a9bcd