Add more accurate percentile to Global Information

[jaakkos]

As Gil mentions in his talk http://www.infoq.com/presentations/latency-response-time
95th and 99th percentiles are not always enough.

[mhjort]

At the moment all the reports are produced using gatling-highcharts which doesn't do that automatically.

However, I have been thinking that clj-gatling should produce it's own simple report that is shown in command line. Then gatling-highcharts would be used only for detailed graphical reports

[mhjort]

Added this to Future milestone because it makes sense to do this after #26 is solved.

[mhjort]

clj-gatling is now using latest Gatling Highchart reporter which has 4 different percentiles. So I think this is solved.