Display /HELP command list more compactly

[DanielOaks]

When you do /quote HELP index, all the commands are listed. In a very inefficient way that's difficult to browse. Instead of the single list, it should list 'em in three columns or something along those lines.

Basically: Make a function that takes a list of strings, a desired line length, a number of columns, and then:

1. Splits the line into X columns.
2. Go through sequentially adding the items, separated by the spaces.
3. If it overruns the column, overflow onto the next column.
4. If it overflows the line, try to put it on a line all by itself?

Something roughly like that, and then display it. ^ can be a function alongside the existing line-splitting function we have for maxlen.

Suggested by @bogdomania :)