Changed output type to stdout for --version and --csv-header.
Addition to "send --json and --csv results to stdout and logs to stderr librespeed#39"

* Update README.md

ups

* stdout for --csv-header and --version

Changed output type to stdout for --version and --csv-header.
Addition to "send --json and --csv results to stdout and logs to stderr #39"

* decimal places at jitter and ping

better values with --share
The browser version doesn't really seem to use decimal places at ping but this
limits/extended ping and jitter to .2 decimal places at --csv / --json and stdout.
this prevent 1.0909090909090908 ping times within csv and json and extend those values in rest of the data.
The ping value could be adjusted to .0 to match the web version but this way the values are more accurate. +1 for the cli.

* Update README.md

Formatting adjusted