std.experimental.randomized_unittest_benchmark is ready for comments

[Robert burner Schadek via Digitalmars-d]

Thank you Seb for taking over the review management.

Some additional feature for the proposed module is.

* Simple way to create test data for user defined types
* Benchmark data is stored into csv file for comparing the 
benchmark results between runs
* Standalone tool to create gnuplot graphs from generated csv 
benchmark files

The long time vision (2+ years) is to have a benchmark for every 
function in phobos and have the resulting graph on the Dlang 
webpage (merged PRs -> webpage). So we can track the performance 
of everything.