wget should be already present on travis
Added -O3 and lapack to travis file
cleaner travis file

I removed all the commands to install latex.
Just as a secure copy, I leave the commands in .travis.install.doxygen
fix lapack for travis
Fixed phase in diagMatrix

Before this fix the phase was chosen enforcing the sum of the elements
of each eigenvector to be positive (see dd4bd09bf).
This does not work well when the
sum is numerically close to zero for some symmetry. With this fix I
set the first non-zero element of each eigenvector to be positive.
Hopefully it is more robust and make results better reproducible
for regtesting
changelog
Decreased precision for regtests
belfast-8: wrong link to tgz
belfast-5: the link to the tar was missing also here
belfast-2: missing link to tar
Merge branch 'v2.1'