Log Message:
math/qrupdate: add package for QR and Cholesky matrix decomposition

This is scheduled to be a dependency for math/octave to support the
named operations.

Qrupdate is a linear algebra library for fast updating of QR and Cholesky
decompositions.

Supported operations:

- QR rank-1 update (qr1up)
- QR column insert (qrinc)
- QR column delete (qrdec)
- QR column shift (qrshc)
- QR row insert (qrinr)
- QR row delete (qrder)
- Cholesky rank-1 update (ch1up)
- Cholesky rank-1 downdate (ch1dn)
- Cholesky symmetric insert (chinx)
- Cholesky symmetric insert (chdex)
- Cholesky symmetric shift (chshx)
- LU rank-1 update (lu1up)
- LU pivoted rank-1 update (lup1up)