Add UI test

Try and download a few things to confirm the UI loads properly

Author: lmgivelaccenture

tests/proxy/ui.t

@@ -0,0 +1,30 @@
+  $ . ${TESTDIR}/setup_test_env.sh
+  $ cd ${TESTTMP}
+  $ curl -s -I http://127.0.0.1:8002/
+  HTTP/1.1 302 Found\r (esc)
+  location: /~/ui/\r (esc)
+  date: * (glob)
+  \r (esc)
+  $ curl -s -I http://127.0.0.1:8002/~/ui/index.html
+  HTTP/1.1 200 OK\r (esc)
+  etag: * (glob)
+  last-modified: * (glob)
+  accept-ranges: bytes\r (esc)
+  content-length: 633\r (esc)
+  content-type: text/html\r (esc)
+  date: * (glob)
+  \r (esc)
+  $ curl -s -I http://127.0.0.1:8002/~/ui/favicon.ico
+  HTTP/1.1 200 OK\r (esc)
+  etag: * (glob)
+  last-modified: * (glob)
+  accept-ranges: bytes\r (esc)
+  content-length: 12014\r (esc)
+  content-type: image/x-icon\r (esc)
+  date: * (glob)
+  \r (esc)
+  $ curl -s -I http://127.0.0.1:8002/a/repo
+  HTTP/1.1 302 Found\r (esc)
+  location: /~/ui/browse?repo=/a/repo.git&path=&filter=%3A%2F&rev=HEAD\r (esc)
+  date: * (glob)
+  \r (esc)