DOC: don't recommend root install

this causes undesirable issues in integration with system packages.
DOC: update debian and ubuntu installations

Drop third party package repository from docs.
It does not provide any newer scipy packages for non obsolete
distributions.

Update the build installation for numpy and debian, especially provide
more information on getting working optimized BLAS.
DOC: document numpys openblas brokenness

see numpy/numpy#4192
DOC: add note about issues with OpenBLAS and fix captialization
Merge pull request #48 from juliantaylor/debian-install

Update documentation of debian source install