IS Layout: Template engine that replaces place holder values

This class is a template engine that searches for place holders tags using regular expressions and replaces them with input values.

The class can use templates defined specified files or takes the template text as an argument.

It can replace template place holder values in the whole template or partially in sections delimited in the template with special identifiers.

It can iterate over a given section to repeat it in the output but using different template input values on each iteration.

It may also include the output of one processed template as input value of another template to be processed.

To generate the final output the class removes all place holders that were not used.