remove download scripts, consolidate into script

most of them were just calling the gitclone script,
so remove them.

the grub script was treating gnulib as a dependency.
i've now added the ability to grab 1 dependency, in
the gitclone script (it should be expanded later to
support multiple dependencies)

the gitclone script has been renamed to "fetch".
the "fetch_trees" script does more or less the same
thing, but calls "fetch" and handles multiple revisions
if a project needs that

this is more efficient, and slightly reduces the code
size of lbmk!

Signed-off-by: Leah Rowe <leah@libreboot.org>

resources/scripts/build/payload/grub

@@ -31,7 +31,7 @@ main()
 	printf "Creating GRUB payloads and configuration files\n"
 
 	[ ! -d "grub/" ] && \
-		./download grub
+		./fetch grub
 	[ ! -f "grub/grub-mkstandalone" ] && \
 		./build module grub
 	[ ! -d "payload/" ] && \

resources/scripts/build/payload/seabios

@@ -53,7 +53,7 @@ check_dependencies()
 	rm -f ${payloaddir}/* || exit 1
 
 	if [ ! -d "seabios/" ]; then
-	    ./download seabios || exit 1
+	    ./fetch seabios || exit 1
 	fi
 }