Documentation

Catching up on documentation of changes and new features that I have added in 3.0.

I've started removing the old J# and old style C++/CLR documentation in the files I touch. J# is dead and if I look at another `__gc` I will further regret the period of my life that I wrote crap like that. :smile:
These <pre> blocks that previously displayed code inline, as opposed to the code blocks, seem to come out looking a bit odd when using the prettyprint class. Maybe we should drop the class in that case. In this case, it is a bit of code, but in some other cases, <pre> is used to show output.

That said, I wouldn't go back at this point, but see how it looks with and without for new stuff.