Implement
- additional DSL tests
- first bits of `action` nodes
- types extraction of a calling function
- passing arbitrary number of parameters to a function
Add `CalculatorDSLTest`

Implement `Calculator with AST nodes production` sample
Implement bunch of examples
- ABC
- Pascal nested comments
- Calculator that produces AST, that is interpreted afterward

Implement processing of anonymous functions that has underscored sections
Implement `optional` and `JSonSimpleParser`
Add `value-stack` tests