add vendor packages避免用户网络太慢无法下载编译

vendor/github.com/pierrec/lz4/README.md

@@ -0,0 +1,31 @@
+[![godoc](https://godoc.org/github.com/pierrec/lz4?status.png)](https://godoc.org/github.com/pierrec/lz4)
+[![Build Status](https://travis-ci.org/pierrec/lz4.svg?branch=master)](https://travis-ci.org/pierrec/lz4)
+
+# lz4
+LZ4 compression and decompression in pure Go
+
+## Usage
+
+```go
+import "github.com/pierrec/lz4"
+```
+
+## Description
+
+Package lz4 implements reading and writing lz4 compressed data (a frame),
+as specified in http://fastcompression.blogspot.fr/2013/04/lz4-streaming-format-final.html,
+using an io.Reader (decompression) and io.Writer (compression).
+It is designed to minimize memory usage while maximizing throughput by being able to
+[de]compress data concurrently.
+
+The Reader and the Writer support concurrent processing provided the supplied buffers are
+large enough (in multiples of BlockMaxSize) and there is no block dependency.
+Reader.WriteTo and Writer.ReadFrom do leverage the concurrency transparently.
+The runtime.GOMAXPROCS() value is used to apply concurrency or not.
+
+Although the block level compression and decompression functions are exposed and are fully compatible
+with the lz4 block format definition, they are low level and should not be used directly.
+For a complete description of an lz4 compressed block, see:
+http://fastcompression.blogspot.fr/2011/05/lz4-explained.html
+
+See https://github.com/Cyan4973/lz4 for the reference C implementation.