Pre-release with multiple updates

This pre-release is for the authors of multiple issues to test the fixes that I made.

Added or enhanced the following features:

• Updated the documentation with missing or inacurate information and best practices
• Created a better "backdrop" the allows interaction with the content of the target element
• Added the "scrollIntoView" options that configures whether or not the tour scrolls after a step is shown
• Merged @diego-vieira's PR that adds the "useHotkeys" option, allowing the tour to be controlled with the keyboard
• Added UI Router integration