* Refactoring update
Overview of changes:
- Renaming of ltcl_code_highlighter* to ltcl_syntax_highlighter*.
- Fine-tuning of regex generation.
- Fine-tuning of order_matches to take into account key words inside of structures.
* file extension
Refactored checking of file extension.
* Refactoring of highlighter
Refactoring of highlighter and adding XML-parser.