Update mouse gem dependency
Change Element#rect to Element#to_rect
DSL#move_mouse_to debug should check to highlight elements

Instead of things that respond to #bounds

Not a whole lot of things respond to bounds that
would be passed to that method, should only be
Elements 99.9999% of the time; so checking the
kind_of? will be faster.
Bump version for development

β isn't enough!
Make DSL#show_preferences_window handle all Elements
Add CONTRIBUTING.markdown
Use only ASCII for version strings to appease RubyGems
Update Copyright year in the README
Add ENGINE information to the version
Update version for 0.9 release
Make Element#ancestor not finding an ancestor
Add DSL#contextual_menu hack
Update documentation for DSL#contextual_menu
Expose new Mouse gestures through DSL