Ability to include jQuery in the <head> (instead of at the end near </body>)

For some clients there is a big benefit in using Embedly on their site. For smooth integration Embedly requires jQuery to be part of the < head>. There are other helpful plugins and services that often can not work well on a webflow site, because of jQuery integration added automatically to the code at the end of the page. Not sure if this has changed, the last time I was trying to resolve something related was back in the summer.

Am I able to include jQuery in the < head> of some pages (or even sites) through the custom code? And if I’m not, is it possible when including it before the < /body> tag of a site, to do a check of some sort and see if maybe it has been included already earlier in the code?