First implementation of util.template()

The util.template function allows for better translations through
dynamic positioning of place markers. The range of place markers
runs from %1 to %99, but normally no more than two or three should
be required. There are no provisions for escaping place markers.

output = util.template{
    _("Hello %1, welcome to %2."),
    name,
    company
}

This function was inspired by Qt:
http://qt-project.org/doc/qt-4.8/internationalization.html#use-qstring-arg-for-dynamic-text
Added unit tests for util.template()
Merge pull request #272 from Frenzie/util.template

First implementation of util.template()