Parallel checks

[dimiro1]

Right now the checks are executed one after another, would be interesting to execute them in parallel.

See: https://github.com/dimiro1/health/blob/master/checker.go#L50

[Freakin]

It would be great to see the checks executed in scheduled goroutines, so longer-running checks aren't executed on every GET.

[mschneider82]

i have implemented @dimiro1 idea in my pull request #24
i also have implemented @Freakin idea in my pull request #25 (includes the above commit)