implement http_Digest Auth, and improve it for rtsp

Conflicts:
	src/zm_remote_camera_http.cpp
	src/zm_rtsp.cpp
merge the rest of my Digest-AUth fixes: This should solve #399
add a changelog entry
add Digest Authentication handling for simple http method.
Fix some indentations in zm_monitor.h
echo the URL to the RTSP device during the OPTIONS directive
Merge pull request #588 from ZoneMinder/digest_auth

Digest auth
Merge pull request #608 from knnniggett/RTSP_mUrl

echo the URL to the RTSP device during the OPTIONS directive
Merge pull request #607 from manupap1/memory_fix_leaks

Fix some memory leaks in zma
Merge branch 'master' into qq