Show graphs of coala performance

[adtac]

between versions (and if it won't be too computationally costly, every n commits to get a smoother graph)

[sils]

so somebody could write a script to measure the performance by running it 5ish times and then we run it for a number of commits? It must be the same machine of course and we may even need an HDD and SSD measurement...

[jayvdb]

Created coala/meta#102

[adtac]

I also wrote a script to automatically do this and posted it as a comment (bad idea, I know). No idea where it went ^^