Create distribution classes
Add test cases
Add .travis.yml
Update README.md
Add .coveralls.yml
Fix README.md example section
BinomialDistribution: Fix for probability
MT19937Engine: Fix a doc comment
Add DiscreteDistribution
Update README.md
AbstractEngine: Add discard() method
Implement LinearCongruentialEngine
Refactor DiscreteDistribution
Add seed() method to AbstractEngine
Refactor DiscreteDistribution
Fix doc comments
Fix syntax error for PHP 5.3
Add __invoke() to AbstractDistribution
Add __invoke() to AbstractEngine
Fix AbstractEngine::nextDouble()