Add UTF-8 support
Add CELL definition
Refactor DSL grammar

Allow for using ans alias ID on the column for better handling. Now
Cell Name/Header is defined as  STRING while using a column identifier
for expressions. Add new data type "fecha".
Add externalized validation

Add validation to DSL and make the messages externalized for language handling.
Refactor templates generators

Module templates for expresions, making the genreation overloaded. Also
fixed some bugs introduced with the DSL grammar refactoring.