Improvements & additions

Closed [previous pull request](https://github.com/perungrad/Templatte/pull/1) because of wrong branch.
It's not a good idea to have templates as php files. The whole point in having a template system is to decouple PHP from the HTML.
Yes, you have more options when the template is a php file, but... do you need a template system when you want to work with php files?