bug fixes in graph_lasso and moving non-custom log-likelihood definition to specific definition of cost
corrected sign error in _objective
pep8 compliance
added test cases to test_graph_lasso for alpha=0
deleted the .orig file in this commit
deleted *.py.orig from branch
cosmetic remarks incorporated
Merge branch 'glbugfixes'
cosmetic remarks, pep8 compliance against trailing white spaces, spelling errors
clean up
Merge pull request #2505 from rphlypo/master

bug fix in GraphLasso/CV and corresponding smoke test + EmpiricalCovariance updates