part 2 of the reorganization. Benefits/changes:
1) Eigen2 co-installable with Eigen1 without conflict, without affecting programs including either.
2) #include<Eigen/Core> without the .h without conflict with the Core/ directory
3) Uniformize coding style of the CMakeLists.
diff --git a/doc/snippets/compile_snippet.cpp.in b/doc/snippets/compile_snippet.cpp.in
index 9f7d568..bc79e25 100644
--- a/doc/snippets/compile_snippet.cpp.in
+++ b/doc/snippets/compile_snippet.cpp.in
@@ -1,4 +1,4 @@
-#include <Eigen/Core.h>
+#include <Eigen/Core>
USING_PART_OF_NAMESPACE_EIGEN
using namespace std;
int main(int, char**)