Removed some L-functions for Siegel modular forms

Eisenstein series and Maass lifts on Sp(4, Z) shouldn't have
L-function links, as these aren't primitive.  On Sp(4, Z) we
now only show them for non-lifted Siegel cusp forms
Added link to (page above) emf for Maass lift.
Merge branch 'siegelLfns'