Removed a redundancy in LFM. Precision operator now properly handles unmasked parameters.

git-svn-id: http://beast-mcmc.googlecode.com/svn@6549 ca793f91-a31e-0410-b540-2769d408b6a1
replaced references in masked parameter in LFM with references to existing parameter of booleans indicating if a data value is continuous or discrete

git-svn-id: http://beast-mcmc.googlecode.com/svn@6550 ca793f91-a31e-0410-b540-2769d408b6a1