relative positionning for list-title is useless and breaks thead on new
page repeat behaviour.
New readFileToString method

ReportBuilder.readFileToString allows including of JS libraries from
Play.current.resource for further processing of all in one HTML files by
wkhtmltopdf.
Make use of new ReportBuilder.readFileToString to include momentJs
library providing missing descent javascript date management.
Include momentJs library providing missing descent javascript date
management.
Clean up.