renamed cv::flann to cv::cvflann to avoid name conflicts

3rdparty/include/flann/common.h

@@ -36,7 +36,7 @@
 
 #include <stdexcept>
 
-namespace flann
+namespace cvflann
 {
 class FLANNException : public std::runtime_error {
  public:

3rdparty/include/flann/flann.hpp

@@ -40,7 +40,7 @@
 
 #include "flann.h"
 
-namespace flann
+namespace cvflann
 {
 
 class NNIndex;

3rdparty/include/flann/matrix.h

@@ -35,7 +35,7 @@
 #include "random.h"
 
 
-namespace flann
+namespace cvflann
 {
 /**
 * Class implementing a generic rectangular dataset.

3rdparty/include/flann/random.h

@@ -37,7 +37,7 @@
 
 using namespace std;
 
-namespace flann
+namespace cvflann
 {
 
 /**