[RP] PATCH - error messages

[Doug Kearns]

G'day all,

I just noticed a number of inconsistencies in the error messages. Here's
a patch which catches most of them.

http://mugca.its.monash.edu.au/~djkea2/ratpoison/error_messages.patch

Other challenges addressed:
- 'definputwidth' no longer accepts negative values and outputs a better
  error message when an illegal argument is given
- '*gravity' were generating the wrong message when an illegal argument
  was given
- '*split' now return an error message for illegal arguments

Other challenges not addressed:
- Yes, I saw the TODO item but I only had 20 minutes - maybe later ...
- Should 'defwaitcursor' accept on/off like 'startup_message' and
  'warp'?
- 'def*padding' generate the incorrect message if non-integers are given
  as arguments
- Does 'defpadding' accept negative arguments intentionally?
- Should the other 'focus*' commands output a message like 'focuslast'
  when the other frame can't be found? I don't really use frames but it
  may just be irritating if they did.

Regards,
Doug

PS. Sorry, but I've just been talking to someone who _refuses_ to talk
about bugs for they are 'challenges' apparently.

"We found 22 new challenges today" ... indeed! :-)