Make collapsing sidebar's conditional colors work correctly!!

[cyrusae]

• [x] Move flagged content and the ability to comment on it to a sidebar
• [x] Make sidebar default to collapsed and do the slide thing
• [x] Include flags (list), buttons to control flagging and ability to comment further on the matter --> Comments are pending #44 / #37
• [x] Have the clickable symbol be a Unicode flag ⚑
• [ ] Make the symbol (and maybe a whole side bar?) change colors depending on whether there are existing flags so I don't forget them