Rearrange Lapack to be like BLAS. Implement cholesky decomposition

Responded to PR comments

modified travis file

Changed input and output types

added back needed types by cgo

Fixed perl script so it compiles

Changes to genLapack to allow compilation

Reinstate test-coverage.sh

native/lapack_test.go

@@ -0,0 +1,17 @@
+package native
+
+import (
+	"testing"
+
+	"github.com/gonum/lapack/testlapack"
+)
+
+var impl = Implementation{}
+
+func TestDpotf2(t *testing.T) {
+	testlapack.Dpotf2Test(t, impl)
+}
+
+func TestDpotrf(t *testing.T) {
+	testlapack.DpotrfTest(t, impl)
+}