Step with backdrop and invalid selector should not attempt to create an overlay element, refs #194
`showStep` should check if tour ended before it tries to display the step, refs #195
removed unnecessary dot
removed `ended()` checks from `prev`, `next` and `goTo` methods, refs #195
Make the docs multipage

- Move the API documentation off the homepage
- Remove the “Contributing” section and add the information to the readme
- Add Jekyll for building the docs
- Add Google Analytics
Don’t build the docs when running `grunt test`
added class with step id to popover element, updated global z-index of tour elements
Watch assets to run jekyll task
Merge branch 'develop' into docs-redesign
Merge pull request #200 from sorich87/docs-redesign

Docs redesign
Add CNAME file
Create standalone build that doesn’t require Bootstrap
Mention that it works without including all Bootstrap
Make navbar position static and Github badge position absolute
Remove unused index file
Add visual test for standalone styles
Mark getState, setState and removeState as private
Match paths with RegEx
improved source code consistency
Merge pull request #202 from sorich87/standalone

Build for websites not using Bootstrap