Remove some files that should not be in source tree, minor changes

Suggestion to clean up a little (to make upstream merge easier in the future)
config.h is auto generated upon configure, 
motion.mk808.conf was temporary experimental config from test branch - it's not needed in the scope of current fork
Restored 0644 permissions for files: CHANGELOG INSTALL ffmpeg.c ffmpeg.h netcam.c netcam_rtsp.c
Added some bugfixes and credits for CHANGELOG