Feature: new template

This pull request adds support for an additional template (highcharts) as alternative for the currently used default template. The template has been built with [bootstrap](http://getbootstrap.com/) and [highcharts](http://www.highcharts.com/).

I reused the `-t` command line parameter to select the template when `highcharts` has been specified but no directory with this name exists.

Regards,
niosHD