Update the "go get" path in the README.

Fixes #12.

README

@@ -1,11 +1,7 @@
 The Snappy compression format in the Go programming language.
 
 To download and install from source:
-$ go get github.com/google/go-snappy/snappy
+$ go get github.com/golang/snappy/snappy
 
 Unless otherwise noted, the Snappy-Go source files are distributed
 under the BSD-style license found in the LICENSE file.
-
-Contributions should follow the same procedure as for the Go project:
-http://golang.org/doc/contribute.html
-