Import constants for remainder of usage

For kXML_RPC_ERROR_OCCURS
Remove unused, make a const CGFloat

- move consts to the standard location
Make NS_ENUM from #defines
#defines to enum, fix ups; fix reply crash

- Xcode built without issue in the last few commits, but now wanted the .h file

- startReply: is no longer the selector to use, composeReply: is