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/git/revisions

@@ -3,7 +3,7 @@
 # Project name is enclosed by curly braces '{}' information about the
 # project relevant to osbmk is stored between the subsequent curly
 # braces. This file is used by the gitcheck script as well as the
-# gitclone script. Each entry must include: revision 'rev', location
+# fetch script. Each entry must include: revision 'rev', location
 # 'loc', and the git url 'url'. Bkup_url is optional.
 
 {coreboot}{
@@ -25,6 +25,7 @@
 	loc: grub
 	url: git://git.savannah.gnu.org/grub.git
 	bkup_url: http://git.savannah.gnu.org/r/grub.git
+	depend: gnulib
 }
 
 {gnulib}{