put all src downloads under src/

build/release/src was partly re-written to accomodate this

memtest86plus was patched to have a central Makefile, and
lbmk modified to use that, rather than mess with build32
and build64. the central Makefile just builds both targets
or cleans both targets

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

script/update/release/roms

@@ -104,7 +104,7 @@ make_archive()
 strip_archive()
 {
 	romdir=${1}
-	[ -d "coreboot/${tree}" ] || \
+	[ -d "src/coreboot/${tree}" ] || \
 		x_ ./update project trees coreboot ${tree}
 
 	x_ ./build coreboot utils ${tree}