Hide Follow-button and 'Follows you' text when not logged in

Closes #14

See merge request !27

Dragging and dropping files into text box attempts to upload them.

See merge request !26

Files dropped into post_status_form text box get sent to media_upload for attachment upload, media_upload reorganized a bit to allow reuse of existing code.

Feature/mark conversations with a red line

See merge request !25

Seems to blow things up.

This reverts commit 9cf438f1.

set top and bottom padding on the bars to be equal because it was too top-heavy

See merge request !24

Make timeline use full width on mobile

See merge request !23

Makes chrome really slow and adds problems with tab synchronization.

They have a span embedded in the link, so let's look at the parent, too.