Improved Mathieu equation eigenvalues and testing

[Brian Gough]

Lowell Johnson writes:
 > I've attached a patch for the Mathieu function eigenvalue accuracy and 
 > testing in the specfunc directory.  Based on input from Brian Gladman, 
 > I've increased the number of terms in the eigenvalue matrix to ensure 
 > double precision accuracy.

Thanks, I've added it and updated the documentation for that function.

-- 
Brian Gough

Network Theory Ltd,
Publishing Free Software Manuals --- http://www.network-theory.co.uk/