dstats Linear Regression

[dsimcha]

I've created a proof-of-concept linear regression module for my dstats
statistics library with an API that makes heavy use of ranges and lazy
evaluation, instead of using a traditional matrix-based approach.  This could
be an interesting demonstration of the kind of high-level functionality that
can be implemented on top of the range primitive, when combined with the new
Phobos and D's other template features.

Docs:
http://svn.dsource.org/projects/dstats/docs/regress.html

Code:
http://dsource.org/projects/dstats/browser/trunk/regress.d