New option "scroll" to enable/disable scrolling

Using this on our homepage is awesome, but we can't have the page scrolling down when it first loads. I'd like to see this as a tip setting eventually, to enable/disable scrolling for each stop of the ride.
Add autoStart so tours can start after page load

See #67 Ability to initiate first tour step manually after page load
a11y improvements
Sandbox tab focus to the modal
Adds aria-labelledby and aria-describedby attributes
Added a check to the destroy function to determine if the joyride object has ever been initialized.  If joyride was never initialized it would throw an error.
Merge pull request #75 from ncloward/master

Destroying Joyride when an instance has never been initialized throws an exception.
Merge pull request #69 from larowlan/master

Adds some a11y improvements to joyride.
Merge pull request #68 from andrew-kzoo/issue-67

Add autoStart so tours can start after page load
Merge pull request #64 from mholt/patch-1

New option "scroll" to enable/disable scrolling
test if li element is defined before calling pos_phone or pos_default functions to avoid undefined error when resizing the window.
Set autoStart to true for joyride in the demo.

Default value of false for the autoStart property is causing the demo
joyride to not run.
Merge pull request #87 from cm0s/master

Avoid Uncaught TypeError: Cannot call method 'offset' of undefined error when using autoStart: false
Merge pull request #93 from bradhuffman/master

Updated demo.html to autoStart joyride.
Added a modal background option, and an expose feature to expose elements on the tour

Change-Id: Ia9a77e8f31cdb29bdb1f0a240eaea99a13d5f0c1

added expose reset to resize event

Change-Id: Ib97130c5b96daa70ccf3ccaa0828ce45ddf81640

A few more tweeks after working out issues with implementation

added a postExposeCallback
improved the way elements are exposed
added expose tracking array to realign all (allowing for more than one) when window size changes
added needed call to methods.un_expose when ride ends.

fixed right side tip placement

fixed methods.corners to calculate based upon the final scroll_to location since the scroll_to likely hasn't finished when corners is being run. Also changed all the checks to allow corners to return false if alignment is equal, since false is what we want for placement

Change-Id: Iae7b2e322769bb661be41ec65ffe09b2791ffe36
Merge branch 'rebase_w_parent'

Conflicts:
	demo/demo.html
	jquery.joyride-2.0.3.js

Change-Id: Ifd2d58c04926b07238dd8dd3f694c574e296327c