Speck: added basic benchmarking.

[ghost]

I added this when I noticed that decrypt performance was significantly slower than encrypt performance.

[ghost]

I am currently getting these results on my laptop (CPU: Intel(R) Core(TM) i7-6700HQ CPU @ 2.60GHz, 16383212 kB DDR4 @ 2133 MHz):

test decrypt      ... bench:          32 ns/iter (+/- 1)
test encrypt      ... bench:          25 ns/iter (+/- 1)
test generate_key ... bench:          36 ns/iter (+/- 1)

Edit: this is with Gnome running, I don't know the effect of it.

[ticki]

Very cool stuff, but before I can merge please fix the comments :)

[ticki]

You don't need this file as it already exists in the root of the repo.

[ghost]

I removed the .gitignore file, I hope that's what you wanted.

[ticki]

Thanks!