I am assuming fixes are being submitted to the dev version on a regular basis. So, is there a way of downloading M2 with all current fixes rolled in?
I tried downloading the developer.zip from GitHub, but after messing with all the composer stuff and installing the additional pre-requisites, the setup wizard still just greets me with "Magento 2.0". Quite disappointing!
It depends on how you originally installed magento 2. if you had a git version, you will do git pull, composer update and then bin/magento setup:upgrade. Documented here.
if you installed via composer create-project or downloaded a zip from magento.com, you can go to System->Web Setup Wizard and go to system upgrade and follow steps there. Also see https://www.magentocommerce.com/download for latest released version.