Added rules for literal int and boolean

LiteralValueUse returns tdl::LiteralValueUse:

    {tdl::LiteralValueUse}

    value=LiteralValue

    (value=STRING | intValue=BIGINTEGER | boolValue=BOOLEAN)

    //TODO: ambiguity if type? value -> temporary solution

    //TODO: add option to have the type after wards without any keyword e.g. 100 s?

//    (dataType=[tdl::DataType|Identifier])?

    END

;

BIGINTEGER returns ecore::EBigInteger:

	INT

;

//## Terminals

terminal BOOLEAN returns ecore::EBoolean:

	'true' | 'false'

;

// The following synthetic tokens are used for the indentation-aware blocks -> moved to extended grammar

//terminal BEGIN: 'synthetic:BEGIN';  // increase indentation

//terminal END: 'synthetic:END';      // decrease indentation