Updating go depencancies. Switching to go1.6 vendoring (#2949)

vendor/github.com/alecthomas/log4go/README

@@ -0,0 +1,14 @@
+# This is an unmaintained fork, left only so it doesn't break imports.
+
+Please see http://log4go.googlecode.com/
+
+Installation:
+- Run `goinstall log4go.googlecode.com/hg`
+
+Usage:
+- Add the following import:
+import l4g "log4go.googlecode.com/hg"
+
+Acknowledgements:
+- pomack
+  For providing awesome patches to bring log4go up to the latest Go spec