[RP] command interactivity

[sabetts]

I made some changes to actions.c mostly. Commands can now be called 
interactively and non-interactively. Right now, using ratpoison -c will call 
the command non-interactively and the colon command and keystrokes call them 
interactively. It is up to the command to behave differently. Currently all 
commands behave the same except for the windows command which, when called 
non-interactively returns a the list of windows as a string which is then 
passed back to the 'client' that issued the command. This brings me to the 
other change: commands can now return strings. Right now, these strings are 
ignored except if they are called through the ratpoison -c mechanism, in which 
case the string is printed (easiest if you try it yourself).

This should allow ratpoison scripting to actually do something useful. You 
could write a script that checked the window list for, say, emacs and if its 
there switch to the window otherwise start it up. Fun fun fun!

Let me know if you have any problems. There are some elusive race conditions 
with the ratpoison -c mechanism that Ryan and I noticed but I've been unable to 
replicate them. Basically stuff starts hanging. Its not fatal, but it could 
mess a script up pretty good. We managed to mess things up by hammering on 
ratpoison in this manner:

while true; do ratpoison -c "next"; done

and then sending keystrokes to split the screen and whatnot. Its easiest to do 
with 2 machines so you can stop the madness :).

If you're looking for something to do, you could write some ratpoison wrapper 
functions for python, perl, elisp, clisp, bash, C, etc to avoid having to type 
ratpoison -c "cmd" all the time. Instead you could type rp_next(), for 
instance. Something to do if you're bored, anyway...