Problems when executors from ext/types threw exceptions

[rafaelverger]

Exceptions thrown by ext/types are being imported based on a different object compared with the expected exceptions in core/controller.ts;

For example when StringSearch receives an empty result from server it throws a ValidatorError extracted from YveBot.exceptions and then controller tries to analyse it by checking if it is an instance of ValidatorError from module ./exceptions. This check results in a fail and then the bot get stuck :/

[rafaelverger]

This error was the reason of #44 :/ so the PR #64 could be reverted since it will cover an "impossible" situation