Added a few missing precompiler guards so that Espresso can be compiled with ELECTROKINETICS but without EK_BOUNDARIES.
Merge remote-tracking branch 'upstream/master' into Merged_EK_newer
lbnode set rho worked only in the case of a single component LB. Fixed this, SHANCHEN test case still fails though.
Added item about ELECTROKINETICS to the NEWS file.
Merge pull request #128 from rempferg/Merged_EK_newer

ELECTROKINETICS