NEW FOR SAGE-1.5

DONE:

* Arithmetic architecture -- completely transition to new arithmetic model

* Fast compiled implementation of matrices. 
     -- need more robustness testing and optimizations; but this can wait. 

* Make rings and other parents immutable (no assign_names) and unique.

* Get rid of mutability for parent structures

* Make all (most) parent structures unique 

* Matrices - implement all the classes using the new carefully *designed* structure.

* (for matrices)  -- the coverage is bad (write way more doctests).

* extend what I've been working on to ModuleElement, including _sub_ and _neg_

* then do _mul_, with fast pathways for both algebra and ring multiplication

* use polynomials as a testbed, i.e. give them proper scalar multiplication semantics

* total rewrite of the coercion module, both to clarify exactly what's
  supposed to happen, and also to aim for greater efficiency  
  (merged into element.pyx)

* transition to numpy

* include weave

* notebook -- many small enhancements
    -- do a demo

* gap 4.4.9

* integrate in Alex's new plotting code

* integrate in Alex's new notebook code

* graph theory package, version 1
    -- do demo

NOT DONE:
* reference manual -- update for new code.

* tutorial -- update to work with new code

* constructions -- update to work with new code

* gdmodule and libgd -- doesn't work on PowerPC OS X for some reason (works on linux)

* fix all broken doctests and relevant code (mainly groups and schemes)

* more build testing

* other code?

* gd build problem on OS X PowerPC that Justin Walker reported

------------------------------------------------------

1.5.0:   * MPFR 2.2.1
         * NUMPY -- included Numpy 1.0  (removed Numeric)
         * WEAVE -- included scipy's weave
         * GAP 4.4.9
         * Notebook facelift and robustness improvements
         * version 0.87.7 of matplotlib.
         * T. Boothby: Include libgd (fast graphics C library) and a Python interface (gdmodule)
         * Kate Minola's readline bugfix -- so SAGE now supports Itanium.
         * Jason Martin's GMP-for-Mac-core2 patch:
                  http://www.math.jmu.edu/~martin/
         * included Martin A's improved signal handling code.
         * notebook improvements:
               - faster switching between worksheets (doesn't pop up new tab or start new SAGE session)
               - Got rid of boxes around everything</li>
               - When cursor enters new box it is at *top* instead of bottom
               - Worksheets are now referred to in the url using their name rather 
                 than their number, just like in a wiki; go to an unused url to 
                 make a new worksheet.
         * added a great new subprocess monitor features, so now even
           if you kill -9 the master, then subprocesses are all
           properly killed off.  Awesome!
         * GMP ecm-6.1.1
         * clisp-2.41
         * readline-5.2
         * FORK!! introduced variant of Pyrex called SageX
         * tons of matrix restructuring.