modifying zepto.qsa to correctly scope selectors

with a dom stucture like that:
``<div><ul><li></li></div>`` 
actual Zepto version isn't capable to find stuff like that:
``$('ul').find('>li');``




it will also fail to properly return nothing when doing stuff like that:
``$('div li',$('ul')[0]);``




this patch in zepto.qsa will solve this two issues