* loading animation * add url to struct tab

* add a mising `&& isspace(buf[0])' that would make the parser skip the link label * swap alt and line: line is the text, alt the URL * text is always defined, at worst is a copy of URL

cmd_{previous,next}_line used COLS and LINES, this adapts them to body_{cols,lines}. While there, also add the ability to scroll when trying to go past the beginning/end of the screen.

clminibufev_set was never set, so it would enqueue the event again...