ri/rdoc do not page correctly

The display program for ri/rdoc depends on being able to popen less/more/pager to do paging of the results. The launch of the pager itself works fine in JRuby, but it immediately terminates after a page of data, probably because to a subprocess of the JVM it does not look like a real terminal. If there's a way to make our popen look like a terminal to subprocesses, it would probably solve this. For now I have forcibly disabled paging in ri, so it will at least output the entire content.