Patch TODO: Initialize only one CURL per thread

Patch TODO: Initialize only one CURL per thread

Fort was reinitializing the CURL object on every HTTP download.
libcurl's documentation recommends against this:

	You need one handle for each easy session you want to perform.
	Basically, you should use one handle for every thread you plan to
	use for transferring.

	(...)

	If you then want to transfer another file, the handle is ready to be
	used again. Mind you, it is even preferred that you re-use an
	existing handle if you intend to make another transfer. libcurl will
	then attempt to re-use the previous connection.

The CURL was moved to the thread state variable, is initialized once per
thread, per validation cycle, and is employed in every HTTP transfer.