Merge pull request #34 from yashke/master

RSpec integration example
Test on Ruby 2.0.0
Use https source from rubygems for development.
Recommend 0.2.0 version in README.
Revert "Use https source from rubygems for development."

Travis chokes on this one.

This reverts commit 506bcdbbfcd3d5e18d3b8a53c2bed4ae438174fa.
Add more badges to README.
we don't support capybara 2.1.0 anyway, yet, so let's be more strict for now and let the tests pass
Revert "we don't support capybara 2.1.0 anyway, yet, so let's be more strict for now and let the tests pass"

This reverts commit 50fdff00406685e3ba5c09c81725d279ad8c5ce0.
Don't use selenium driver symbol for tests.
Removing since 1.9.2 is not supported by modern capybara.