* `Benchee.benchmark/3` now doesn't run the benchmark anymore but sim…

…ply adds it to `:jobs` in the config. The whole benchmark suite is then run via `Benchee.measure/1`. This only affects you if you used the more verbose way of defining benchmarks, `Benchee.run/2` should still work as expected.

* the defined benchmarking are now preserved after running the benchmark under the `:jobs` key of the suite. Run times are added to the `:run_times` key of the suite (important for alternative statistics implementations)

* configuring a warmup time to run functions before measurements are taken can be configured via the `warmup` key in the config defaulting to 2 (seconds)
* additionally supply the total standard deviation of iterations per second as `std_dev_ips` after `Benchee.Statistics.statistics`
* statistics in console output are aligned right now for better comparisons
* last blank line of console output removed

* if no time/warmup is specified the function won't be called at all

Initial release