Get rid of autoconf warnings, remove unnecessary manpage section

Renaming configure.in to get rid of warnings.

I don't really "agree" with the removal of start/stop/pause/etc. commands, but this removes them from the man page.
I feel those commands were useful, and didn't add much extra weight to ncmpcpp. I realize that mpc does the same thing, but I don't personally have mpc installed and always used ncmpcpp for my scripting. >.<