Use a vendor directory for repeatable builds - fixes #816

This is using godep to manage the vendor directory.

vendor/bazil.org/fuse/fuse_darwin.go

@@ -0,0 +1,9 @@
+package fuse
+
+// Maximum file write size we are prepared to receive from the kernel.
+//
+// This value has to be >=16MB or OSXFUSE (3.4.0 observed) will
+// forcibly close the /dev/fuse file descriptor on a Setxattr with a
+// 16MB value. See TestSetxattr16MB and
+// https://github.com/bazil/fuse/issues/42
+const maxWrite = 16 * 1024 * 1024