Check the go version

Author: Quentin Perez

goversion.go

@@ -0,0 +1,3 @@
+// +build go1.5
+
+package goversion

goversion_unsupported.go

@@ -0,0 +1,7 @@
+// +build !go1.5
+
+package goversion
+
+func error() {
+	`Bad go version, please install a version greater than or equal to 1.5`
+}