Modernize Examples

[sweemer]

As discussed in #1758 (comment), here is a first pass at modernizing the examples by introducing auto and ext::make_shared. I also removed spaces between angle brackets for a more modern feel.

I tried to preserve the existing formatting as much as possible, but feel free to reformat the changed lines if you prefer.

We can add auto in a lot more places, both in the examples and the main library, just let me know if you think now is the time.

[coveralls]

coverage: 71.903%. remained the same when pulling 6f64993 on sweemer:modernize-examples into aff1e87 on lballabio:master.

[lballabio]

Thanks! I just made a couple of other changes that jumped at me when I looked at the PR.

I wouldn't put too much effort into modernizing the library per se. We're changing things often enough in there that we can add some autos here and there as we already work on some files.