moved margin to the default options
Default scrollView options to an empty hash

Create an empty hash if no options were passed in so the setOptions
function will fire and the drag and friction options will be set.  Not
doing so prevents momentum scrolling on iOS when scrollView is loaded
without options
Merge remote-tracking branch 'upstream/master'

Conflicts:
	Scrollview.js
no need to call the callback when hiding as it will
be called when the state is set.

fixes #30
Merge pull request #31 from pusherman/master

Fixes issue #30