Customise Medium editor

This is a bigger job than what I'm writing here. We have a site where you can build a page of content by adding multiple textareas. Right now it has TinyMCE editor working on these but we have a dev page where we are trying to use Medium Editor ([login to view URL]). I have already got Medium editor working on the textareas, but I need someone to finish coding the image upload extension (i.e. where the images will be uploaded to...I have implemented the extension for this [login to view URL]) and I need you to code an autosave feature which saves the content every 10 seconds or something like that. HOWEVER, none of this needs to be done until one thing has been investigated first. On tinyMCE editor there is the option to switch on the 'source code' button which allows us to switch between the html code and the output text (i.e. so we can see tags etc and edit directly in the source). We need this on the Medium editor. There is no extension for it as far as I can see, so here is a link to building extensions for Medium: [login to view URL] I need to know if it's possible to add a 'source' button on this editor which allows you to switch the view in the textarea. If you can do this, then the rest of the job will be yours too.