gonum: add Version query function

doc.go

@@ -0,0 +1,12 @@
+// Copyright ©2019 The Gonum Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Gonum is a set of packages designed to make writing numerical and
+// scientific algorithms productive, performant, and scalable.
+//
+// Gonum contains libraries for matrices and linear algebra; statistics,
+// probability distributions, and sampling; tools for function
+// differentiation, integration, and optimization; network creation and
+// analysis; and more.
+package gonum // import "gonum.org/v1/gonum"