Merged in rmlarsen/eigen (pull request PR-179)

Prevent crash in CompleteOrthogonalDecomposition if object was default constructed.
diff --git a/Eigen/src/QR/CompleteOrthogonalDecomposition.h b/Eigen/src/QR/CompleteOrthogonalDecomposition.h
index e71944f..230d0d2 100644
--- a/Eigen/src/QR/CompleteOrthogonalDecomposition.h
+++ b/Eigen/src/QR/CompleteOrthogonalDecomposition.h
@@ -397,6 +397,10 @@
 
   const Index rank = m_cpqr.rank();
   const Index cols = matrix.cols();
+  const Index rows = matrix.rows();
+  m_zCoeffs.resize((std::min)(rows, cols));
+  m_temp.resize(cols);
+
   if (rank < cols) {
     // We have reduced the (permuted) matrix to the form
     //   [R11 R12]