Added matcher toBeFocused(element) to README.
Added matcher toBeFocused(element) to README.

almazhou/jQueryTest,FernandoMueller/jasmine-jquery,nicinabox/jasmine-jquery,beni55/jasmine-jquery,wbye/jasmine-jquery,asabaylus/js-fixtures,willprice/jasmine-jquery,jhartikainen/js-fixtures,FernandoMueller/jasmine-jquery,wbye/jasmine-jquery,pivotal/jasmine-jquery,SimenB/jasmine-jquery,velesin/jasmine-jquery,SimenB/jasmine-jquery,badunk/js-fixtures,jhartikainen/js-fixtures,asabaylus/js-fixtures,beni55/jasmine-jquery,willprice/jasmine-jquery,pivotal/jasmine-jquery