Cached TemplatEze: Template engine based on replacement with caching

This class is a fork of the TemplatEze variable replacement based template engine written originally by David Agar.

Here follows the list of added, removed or changed features:

+ Added Template Set support
+ Added perfomance measurement
+ Added Content Caching
+ Added Output Buffering
+ Added array assignment to assign() function
- Removed 'Change Tag' feature
- Removed Error Tracking feature: faster, but not safe :)
* Functions set(), setloop() and tplblock() merged into one assign() function
* Code cleaned up and some functions renamed for more readability
* substr_replace() used instead of str_replace() in _loop() function
* Template sintax changed for more readablity