DecoderControl: move functions into the class
UpdateRemove: Mutex/Cond instead of GMutex/GCond
test/run_tcp_connect: delete obsolete source file
input_internal.h: add extern "C"
input/file,mms: convert to C++
input/rewind: convert to C++
input/ffmpeg: convert to C++
input/cdio_paranoia: convert to C++
despotify_utils: add missing copyright header
despotify_utils: include cleanup
despotify_utils: fix indent
input,playlist/despotify: convert to C++
input/archive: fix memory leak in error handler
FileSystem: extract DirectoryReader, improve the rest

- DirectoryReader is extracted to separate header
- FileSystem.cxx/FileSystem.hxx/DirectoryReader.hxx moved to fs/ subdir
- Functions return true on success, instead of 0 (where applicable)
- ReadLink return result instead of out parameter
- UnlinkFile is renamed to RemoveFile
- CheckExists/CheckIsRegular/CheckIsDirectory are renamed
  to PathExists/FileExists/DirectoryExists
Path: move to fs subdirectory
Makefile.am: introduce libfs