Misc refactoring, e.g. alignment of how modules save tracks and playlists, incl
use of mfi and pli. Also try to avoid direct calls between library and player.
Thanks to Denis Denisov and cppcheck for notifying about the below. The leaks
are edge cases, but the warning of dereference of avail in alsa.c points at
a bug that could probably cause actual crashes.
[src/evrtsp/rtsp.c:1352]: (warning) Assignment of function parameter has no effect outside the function. Did you forget dereferencing it?
[src/httpd_daap.c:228]: (error) Memory leak: s
[src/library.c:280]: (warning) %d in format string (no. 2) requires 'int' but the argument type is 'unsigned int'.
[src/library.c:284]: (warning) %d in format string (no. 2) requires 'int' but the argument type is 'unsigned int'.
[src/library/filescanner_playlist.c:251]: (error) Resource leak: fp
[src/library/filescanner_playlist.c:273]: (error) Resource leak: fp
[src/outputs/alsa.c:143]: (warning) Assignment of function parameter has no effect outside the function. Did you forget dereferencing it?
[src/outputs/alsa.c:657]: (warning) Possible null pointer dereference: avail
[src/outputs/dummy.c:75]: (warning) Assignment of function parameter has no effect outside the function. Did you forget dereferencing it?
[src/outputs/fifo.c:245]: (warning) Assignment of function parameter has no effect outside the function. Did you forget dereferencing it?
[src/outputs/raop.c:1806]: (warning) Assignment of function parameter has no effect outside the function. Did you forget dereferencing it?
[src/outputs/raop.c:1371]: (warning) %u in format string (no. 1) requires 'unsigned int' but the argument type is 'signed int'.
[src/outputs/raop.c:1471]: (warning) %u in format string (no. 1) requires 'unsigned int' but the argument type is 'signed int'.
[src/outputs/raop_verification.c:705] -> [src/outputs/raop_verification.c:667]: (warning) Either the condition 'if(len_M)' is redundant or there is possible null pointer dereference: len_M.
