Internal (Symbols): Added code for symbols, optionals, literals, etc

* BNFE_COMPONENT: Added `deep_out' to returns its parent
Production.deep_out
* BNFE_PRODUCTION: Added call on `a_part' for set_production of Current.
* BNFE_PRODUCTION_KIND: Added symbol check and is_optional for literal
marking
* ECF: Added vision and editor libs
* BNFE_BASE: Added symbol checking and bnfe_type stripping/out.
* Added and improved various tests.