Remove obsolete Selenium functionality

- Also remove all runner-specific config from Jasmine config. Notably,
  result_batch_size is no longer configured through Jasmine::Config, for
  the default runner, override the runner lambda to change this value.
- People wishing to run jasmine tests in selenium should look at the
  jasmine_selenium_runner
  (http://github.com/jasmine/jasmine_selenium_runner)