fixes very slow report generation

this should fix the following issue:
https://github.com/masterthought/jenkins-cucumber-jvm-reports-plugin-java/issues/87

From Pierre Saelens:
the slowness is related to unicode conversion : we have a large file (10 Mb) with a lot of (around 40000 matches)  unicode character (eg.: \u0027)
During parsing, there is a call to Util.U2U which will replace that unicode character with a regex.
With U2U call :

     creating report builder ....
     report builder created.
                size|                time
     -----------------------------------------
                9 MB|         0:19:54.118
     generating report ....
     report generated in 3355 ms

Without :

     creating report builder ....
     report builder created.
                size|                time
     -----------------------------------------
                9 MB|         0:00:19.239
     generating report ....
     report generated in 3444 ms

And the HTML report is the same.

So It's not necessary to replace unicode during parsing.