things for 3.0

[John W. Eaton]

I'd like to do the following for 3.0.

  * Update various README files.

  * Update NEWS file.  There is no way we are going to try to mention
    all the changes since 2.0.17 or even 2.1.73, but we should mention
    important user-visible changes that could cause backward
    compatibility problems.  Are there additional items that we should
    mention?

  * Update the refcard.

  * Update installation instructions.

  * Remove obsolete files (for example, is FLEX.patch still needed?)

  * Any other similar items?

As none of these items involve code in Octave itself, I think they
should be safe to do between 2.9.15 and 3.0 with little testing.

Comments?

jwe