Fix build on rbx (it failed previously)
Merge pull request #1306 from abotalov/fix_rbx_build

Fix build on rbx (it failed consistently previously)
optimization of Capybara::RackTest::Node#unnormalized_text
Merge pull request #1309 from twalpole/visible_optimization

Optimization of Capybara::RackTest::Node#unnormalized_text while checking visibility