Self-text expando and comment max height

Relates to #1497.

~~I'm not sure how feasible it is to add the same kind of option for comment max height (as requested), since we'll have to deal with inline expandos (i.e. when an expando is opened, override the max-height style in the current .usertext-body element, and when an expando is closed check if it is the last one in this comment to be closed [preferably: check if closing it will reduce the comment's height to within the specified max height] and remove the override).
I don't know if that much work would be worth it.~~

**Edit:** This now applies a max-height to both text expandos and comments, and adjusts their height to the largest expando within them (and at least the specified height).

Tested with all expando types (AFAIK).
Sounds good, I think I actually had it formatted normally until I saw it formatted that way (on lines 301, 466, 532, 554, 615, 707, 709, 725-733 [looks better in short form, though], 1077, 1079, 1144, 1670, 1673, etc. of showImages.js) so I thought it was okay :P

At least I think those are all formatted incorrectly (found with this regex: `\tif ?\(.*;\r` ).

I'm now somewhat tempted to go through the entire codebase and fix (most of) them [where there isn't an obvious downside], but replacing by hand would be tedious and using a script could cause other problems.