Add scripts to automatically build libcurl dependency package for Windows; enable dependency downloads for Windows builds.
Change-Id: I962ed38236601b7384ad0484688d986abf572103
Reviewed-on: http://review.couchbase.org/38868
Reviewed-by: Chris Hillery <ceej@couchbase.com>
Tested-by: Chris Hillery <ceej@couchbase.com>