stalls in connection thread. perform most file checking in fserve but allow
for m3u file override and using the Host header if available.
svn path=/icecast/trunk/icecast/; revision=9462
thread by using generic write routine. small leak plugged on failure case.
extend mime type handling slightly for rare case
svn path=/icecast/trunk/icecast/; revision=9440
the same time. Flag clients on return from select/poll and only process those.
Also fix a rare race which could leave clients in pending
svn path=/icecast/trunk/icecast/; revision=8070