Implement naive error reporting (i.e. track latest error occurred)
Add `examples` project. It contains `parboiled-v1` and `parboiled-v2` simple calculator examples
Implement `first parse error` strategy to find error. I.e. find furthest matched `pos` in `input`

Implement simple debugging tracing
Implement `ErrorUtils`. It searches expected `Rule` in accordance with error posistion
Move `calculators` examples to another namespace
Fix `error reporting` tests spec
Fix bug: correctly determine if parsing errors were or not

Rename `debug` argument