popup windows are positioned on the center of a target element
user can select target element using jquery selectors
only modal windows are used in the phone mode
Merge remote-tracking branch 'kyakovenko/master'

Conflicts:
	joyride-2.1.css
Clean up data-selector implementation
Revert "Merge remote-tracking branch 'kyakovenko/master'"

This reverts commit c4ca0595f2cf04ef3f414c9558c46d3f6d6715a8, reversing
changes made to 940a602912634de89028fef952822e2c950f7e3e.

Conflicts:
	jquery.joyride-2.1.js
Add and option "requireTarget" default to false.
Make the steps happen asynchronously to accomodate potential changes that may happen in the pre/postStepCallbacks.