Found with readability-uppercase-literal-suffix
Signed-off-by: Rosen Penev <rosenp@gmail.com>

This doesn't work because IterableSplitString() returns its elements
by value.

Fixes clang warning:

 loop variable 'i' is always a copy because the range of type 'IterableSplitString' (aka 'BasicIterableSplitString<char>') does not return a reference [-Werror,-Wrange-loop-analysis]

Found with bugprone-suspicious-missing-comma
Signed-off-by: Rosen Penev <rosenp@gmail.com>

Found with readability-string-compare
Signed-off-by: Rosen Penev <rosenp@gmail.com>

Found with performance-unnecessary-value-param
Signed-off-by: Rosen Penev <rosenp@gmail.com>

Merge remote-tracking branches 'neheb/uniq', 'neheb/bool', 'neheb/loop', 'neheb/bool2', 'neheb/perf', 'neheb/void' and 'neheb/value'

Found with modernize-pass-by-value
Signed-off-by: Rosen Penev <rosenp@gmail.com>

Found with modernize-redundant-void-arg
Signed-off-by: Rosen Penev <rosenp@gmail.com>

Found with performance-for-range-copy
Signed-off-by: Rosen Penev <rosenp@gmail.com>

Found with readability-simplify-boolean-expr
Signed-off-by: Rosen Penev <rosenp@gmail.com>

Found with modernize-loop-convert
Signed-off-by: Rosen Penev <rosenp@gmail.com>

Found with modernize-use-bool-literals
Signed-off-by: Rosen Penev <rosenp@gmail.com>

Found with modernize-avoid-bind
Signed-off-by: Rosen Penev <rosenp@gmail.com>

Found with modernize-make-unique
Signed-off-by: Rosen Penev <rosenp@gmail.com>

Found with modernize-use-override
Signed-off-by: Rosen Penev <rosenp@gmail.com>

max_frames is size_t, not unsigned long. Fixes GCC warning.

On some VBR files, the single-step interpolation was very inaccurate
and inacceptable.

Closes https://github.com/MusicPlayerDaemon/MPD/issues/720