Simplify .travis.yml
Use Y parameter of LOBPCG in algebraic_connectivity

Y is used to directly eliminate the nullspace of the Laplacian matrix.
Merge branch 'master' into fiedler

Conflicts:
	.travis.yml
Supply array input to lobpcg in algebraic_connectivity
Merge branch 'fiedler' into fiedler_nochol

Conflicts:
	.travis.yml