Support http server redirects

This change sets the libcurl option to support http redirects and adds debug messages showing what is happening.  I did this because we are looking into using dCache as a stratum 1, and its low-bandwidth http server uses http redirects to direct requests to different high-bandwdith pool servers.  I tested it using the apache Redirect option which sends a 302 code, and also added code for other 30x redirect codes that are in HTTP 1.0 & 1.1 standards according to wikipedia but did not test them.