scroll-conservatively default (was: Re: recenter-top-bottom)

[Dan Nicolaescu]

Richard Stallman <address@hidden> writes:

  > I set `scroll-conservatively' to a large value just so it will always
  > be bigger than the screen height.  This means, more or less, that if
  > Emacs can bring point onto the screen by scrolling, with even one line
  > of overlap with the old screen, it should do so.

Then please let's do this by default. The current default of 0 for 
`scroll-conservatively' does not seem to be very helpful.

I would also argue that the default for scroll-preserve-screen-position
should also be changed.