Check in the vendor directory

Travis seems to be having issues pulling deps, so we'll have to check in
the vendor directory and prevent the makefile from trying to regenerate
it normally.

vendor/github.com/json-iterator/go/jsoniter.go

@@ -0,0 +1,18 @@
+// Package jsoniter implements encoding and decoding of JSON as defined in
+// RFC 4627 and provides interfaces with identical syntax of standard lib encoding/json.
+// Converting from encoding/json to jsoniter is no more than replacing the package with jsoniter
+// and variable type declarations (if any).
+// jsoniter interfaces gives 100% compatibility with code using standard lib.
+//
+// "JSON and Go"
+// (https://golang.org/doc/articles/json_and_go.html)
+// gives a description of how Marshal/Unmarshal operate
+// between arbitrary or predefined json objects and bytes,
+// and it applies to jsoniter.Marshal/Unmarshal as well.
+//
+// Besides, jsoniter.Iterator provides a different set of interfaces
+// iterating given bytes/string/reader
+// and yielding parsed elements one by one.
+// This set of interfaces reads input as required and gives
+// better performance.
+package jsoniter