Was not passing in the generic modal-overlay class. (ExpandableModal
doesn't provide it automatically so you can omit it and make a totally
custom overlay if you want.)
Extends lbryuri.build() and lbryuri.parse() to support special
keys, contentName and channelName. These put the right values in the
"name" and "path" position for both anonymous claims and channel
content claims, which lets us write code that can deal with either type
without special logic.
