Merge branch 'master' of https://github.com/Itseez/opencv into add_bs_tutorial

Conflicts:
	modules/stitching/src/motion_estimators.cpp

diff --cc modules/stitching/src/motion_estimators.cpp
index b09253c,d6fd227..7c0b019
--- 1/modules/stitching/src/motion_estimators.cpp
--- 2/modules/stitching/src/motion_estimators.cpp
+++ b/modules/stitching/src/motion_estimators.cpp
@@@ -259,8 -253,8 +253,8 @@@ bool BundleAdjusterBase::estimate(cons
      bool ok = true;
      for (int i = 0; i < cam_params_.rows; ++i)
      {
-         if (std::isnan(cam_params_.at<double>(i,0)))
-         {
+         if (cvIsNaN(cam_params_.at<double>(i,0)))
 -        {
++              {
              ok = false;
              break;
          }