Modified the other examples to use the default camera instead of prov…

…iding their own.

Where appropriate, of course.

The arcball example still explicitly provides a camera, even though it's actually the same as the default camera we'd get. But the point of that example is to show how to create and use an ArcballCamera, so it seemed counter-productive to take it out...

Naturally the imageview example still uses an OrthoCamera, too.

example/basic.cpp

@@ -20,10 +20,7 @@ class ExampleRenderer : public vgl::Renderer
 int main(int argc, char** argv)
 {
   ExampleRenderer renderer;
-  vgl::BaseCamera camera(
-      vgl::Vec3f(0, 0, 5), vgl::Vec3f(0, 0, 0), vgl::Vec3f(0, 1, 0),
-      -1, 1, -1, 1, 30, 800, 600);
-  vgl::Viewer viewer("Example Viewer", 800, 600, &renderer, &camera);
+  vgl::Viewer viewer("Example Viewer", 800, 600, &renderer);
   viewer.run();
 }
 

example/styled.cpp

@@ -50,10 +50,7 @@ class ExampleRenderer : public vgl::Renderer
 int main(int argc, char** argv)
 {
   ExampleRenderer renderer;
-  vgl::BaseCamera camera(
-      vgl::Vec3f(0, 0, 5), vgl::Vec3f(0, 0, 0), vgl::Vec3f(0, 1, 0),
-      -1, 1, -1, 1, 30, 800, 600);
-  vgl::Viewer viewer("Example Viewer", 800, 600, &renderer, &camera);
+  vgl::Viewer viewer("Example Viewer", 800, 600, &renderer);
   viewer.run();
 }