Remove redundant yet unstable test_spectral_lobpcg_mode

The lobpcg mode is already tested in the test_spectral_clustering test.

LinAlgError was raised when executing test_spectral_lobpcg_mode on some
systems depending on the version of the scipy and LAPACK libraries.
DOC: clear up the big elastic net confusion (I hope)

Several users have asked for LogReg w/ E-net (e.g. #3023). Did some
additional copyediting.
Merge pull request #3025 from ogrisel/remove-unstable-lobpcg-test

[MRG] Remove redundant yet unstable test_spectral_lobpcg_mode
Set travis to test old versions of numpy and scipy too
More robust and informative bayes regression test
Skip known failure in scipy 0.11.0
ENH: simplify travis setup
Switch back to the miniconda installer for faster install
WIP trying configure the conda env to be as fast as on master
WIP new tentative to better control MKL, ATLAS and coverage
condition tests were all wrong
typo