no eigen in readDmat

Former-commit-id: 98ce98477e6c3e3c6ed82a8cd5275db4ed88ff55

include/igl/readDMAT.cpp

@@ -2,8 +2,7 @@
 
 #include "verbose.h"
 #include <cstdio>
-
-#include <Eigen/Dense>
+#include <iostream>
 
 // Static helper method reads the first to elements in the given file
 // Inputs: