StepNode - added keyword, keywordType (keyword in English)
Normalize StepNode types And, But to Given, When, Then.
Remove tests for languages en-old, uz.

Tests for those languages are removed because in cucumber/gherkin
definition they have repeated keywords:
- en-old has words "Tha", "Ða", "Þa" as keyword for When and Then,
- uz has word "Агар" as keyword for Given and When.
Optimized Lexer::getStepKeywordType
Merge pull request #69 from kibao/feature/step-node-localized-keyword

StepNode localized keyword