rm shader, tutorial uses new viewer refactor

tutorial/306_EigenDecomposition/main.cpp

@@ -1,7 +1,7 @@
 #include <igl/eigs.h>
 #include <igl/cotmatrix.h>
 #include <igl/massmatrix.h>
-#include <igl/viewer/Viewer.h>
+#include <igl/opengl/glfw/Viewer.h>
 #include <igl/parula.h>
 #include <igl/read_triangle_mesh.h>
 #include <Eigen/Sparse>
@@ -38,8 +38,8 @@ int main(int argc, char * argv[])
   }
   U = ((U.array()-U.minCoeff())/(U.maxCoeff()-U.minCoeff())).eval();
 
-  igl::viewer::Viewer viewer;
-  viewer.callback_key_down = [&](igl::viewer::Viewer & viewer,unsigned char key,int)->bool
+  igl::opengl::glfw::Viewer viewer;
+  viewer.callback_key_down = [&](igl::opengl::glfw::Viewer & viewer,unsigned char key,int)->bool
   {
     switch(key)
     {