input: remove pausing command prefixes

These are now equivalent to combining commands with the "cycle pause" or
"set pause" commands, and thus are not needed anymore. They were also
obscure and undocumented.
manpage: minor corrections
demux_playlist: fix m3u detection logic

Caused failure to detect .pls files, because they were misdetected as
m3u. The problem is that "forcing playlist files" and "forcing a
specific playlist format" are not really treated separate, and in both
cases p->force is set to true. This made m3u detect all files as m3u
if --playlist was used. So correctly check whether the file format is
actually being probed or not.
build: removed undefined behavior from PVR check

This shouldn't matter, but it's probably better if the code to check is
valid - otherwise an extremely clever compiler might fail to compile it,
and the feature would be misdetected. (Probably.)

Found by cppcheck.
player: don't assign "false" to pointer

This is legal in theory. "false" expand to 0, and 0 is a valid pointer
value. But I guess this was not really intended.

Found by cppcheck.
wayland: fix unchecked malloc usage

Found by cppcheck.

Actually untested. (This is the file drag&drop code, I don't even know
which wayland clients support this.)
audio/out: more debugging info for --dump-stats
mixer: make code more readable

You wouldn't have guessed that the bottom-most "level[i] = 0.f;" line
was actually required. It even confused cppcheck.
manpage: update --playlist entry
TOOLS/stats-conv: draw playloop and AO thread events separately

Use for all AO thread events y=0.5, while playloop events remain at y=1.
This makes the graph easier to read.