Update readme and examples

Addresses issue #290 by updating `README.md` and also by moving the Windows examples installation to where the `README.md` said they were (at the top level rather than under doc).

This also fixes #259 by preventing example binaries from being installed from a Debug build.

And I updated the version number examples in `README.md` to 3.5.

@mjhmilla and @chrisdembia, please review. Chris, I didn't try the installation on Linux to make sure I didn't mess up anything with the example installation (they should still go to the same place, but not for Debug builds). Also, it would be worth a quick check of the instructions for different platforms to see if they still match reality.
> better to install cmake files to cmake/ on Windows.

Yep, and that's where they are! It's wrong in README.