Fix typo Matlab->Meshlab.

Change-Id: If64a1e2bd10637eac8ed74a5c43cfa133c7aa575

examples/bal_problem.cc

diff --git a/examples/bal_problem.cc b/examples/bal_problem.cc
index fa1d82a..1ee3c81 100644
--- a/examples/bal_problem.cc
+++ b/examples/bal_problem.cc
@@ -177,7 +177,7 @@
   fclose(fptr);
 }
 
-// Write the problem to a PLY file for inspection in Matlab or CloudCompare.
+// Write the problem to a PLY file for inspection in Meshlab or CloudCompare.
 void BALProblem::WriteToPLYFile(const std::string& filename) const {
   std::ofstream of(filename.c_str());