spec for eigenpairs

Added new methods, inspired on SPSS matrix methods: e_mult, e_quo, ms…

…sq, eigen, eigenpairs, ln, sqrt, sscp

Updated to v0.2.3

Bug fix on Matrix#dup. Doesn't works on Ruby1.9.2

Works on Ruby 1.9.2. Fixed conflicts between old and new Matrix imple…

…mentation

#build adapted from Ruby 1.9.2

First gem and gitified version

The code does not work anymore in Ruby1.9 and the problem was the

"funcall" function. Some methods were changed in 1.9 so, I replaced the 
line

self.funcall(init_method, *argv)

with

__send(init_method, *argv)