Add support for cloning over http

This patch implements basic support for cloning over http, based on the
work on git-http-backend by Shawn O. Pearce.

Signed-off-by: Lars Hjemli <hjemli@gmail.com>
diff --git a/Makefile b/Makefile
index e1436a3..78aad10 100644
--- a/Makefile
+++ b/Makefile
@@ -56,6 +56,7 @@
 OBJECTS += parsing.o
 OBJECTS += shared.o
 OBJECTS += ui-blob.o
+OBJECTS += ui-clone.o
 OBJECTS += ui-commit.o
 OBJECTS += ui-diff.o
 OBJECTS += ui-log.o