Benchmarks

[rexim]

We already have a bunch of issues under the performance tag.

But before working on them, it would be good to have some benchmarks on our hands. For beginning, we can implement something really simple, like an average execution time of the pacmacs-tick function.

Also it would be good to combine this with the integration testing #77

[rexim]

Yeah, it should definitely be a part of the integration testing.