support setting the number of channels for flac and vorbis

typo

use fd instead of pid for tx locking c->iev.ibuf.pid is our pid, not sure why, but fd is just as well as easier to use.

add the fzf example

document jump

add `jump' subcommand to play the first matching

change res->file to be a path instead of a FILE *

print status after play, toggle, restart, next and prev commands

reflow + grammar

improve manpage

update readme

print the "> " prefix only if -p is given the prefix is nice to see, but can break the amused show | filters ... | amused load because sort(1), uniq(1) etc don't know how to strip the "> " and " " prefixes obviously.

add some examples

rewrite `load' to use the new transaction messages this allows to do stuff like amused show | some shell filtering | amused load without the dangers of races between show and load.

add IMSG_CTL_BEGIN/COMMIT to load a playlist in a transaction