CustomActions into custom.c. Cleaned up a lot of the handling of
  custom actions including scripting actions and processing return
  codes.
- Mike McCormack pointed out that MsiFormatRecord is basically the
  same as internal function deformat_string. So broke deformat_string
  out and updated it to function as MsiFormatRecord and implemented
  MsiFormatRecord.
- A number of random fixes to action.c including properly calculating
  the length for the LocalPackage name, not forcing a reboot when
  really we should just return ERROR_INSTALL_SUSPEND and handling
  REG_MULTI_SZ now that we can deformat the properly.