Completed multi-templates feature.

Hello friends, 

I just completed the multi-templates features. Using this feature, you would be able to create your own codegen templates without having to mess up with the current set. You can have more than one templates and choosing one among multiple is easy by just altering the variable introduced in the configuration.inc.php file.

Using this feature, we can have multiple templates and templates could be built like plugin. For example, we could ship QCubed with templates having the old template set as well as jQCubed ones. One may also create another set from scratch or base his own templates from existing ones without worrying about losing the original ones - just copy the existing ones into new directory and update the CODEGEN_TEMPLATES_PATH in the configuration file. 

A few readme files have been updated to suit the new structure. The feature is ready for test. 

Regards