1) Okay, I will add some kind of caching to fall back to in case google doesn't answer (currently the app starts without ads OR pro features and tries to get the license state three times - if that succeds you gett full pro features, if it fails it switches the ads on). This will definitely be in the next update, but that has to wait for a library update from google as I started using some new functionality that can currently cause benign-but-annoying crashes when re-opening the app after after it is evicted from memory -.-
2) Just displaying it should be a doozy, the handling for all kinds of custom column data retrieval is already there. Creating such a column in a test library and making sure the html gets decoded correctly should not pose a problem, I already do that for ne normal comments after all
