2015/12    updated GSL requirements; added imports of 'sna' functions; added network to depends; shortened BIC example. 
2014/01    removed inv_sigma02 term from omega2 update (thanks to Robin Gong). 
2014/01    fixed bug in use of start function when using largest connected component only and edge covariates.
2013/10    checked for leaks using AddressSanitizer, moved some Depends to Imports.
2013/05    now if mclust fails Fruchterman-Reingold is (re)called until mclust can find clusters. 
2013/05    changed setting of seed. A single set.seed is now used. 
2013/04    plugged memory leak due do diagonal of sociomatrix and corrected case-control usage.
2013/04    fixed bug in convergence check for V_xi_* and V_psi2_* (thanks for Triona Ryan).
2013/02    fixed bug in random effects updates and tweaked plot function.
2013/02    fixed bug in predict function for random effects models.
2013/01    changed onAttach to onLoad in zzz.R
2012/08    fixed bugs in handling of nodal covariates and cast same as sender, receiver or social. 
2012/08    working startup message. 
2012/08    fixed V_xi_e and V_psi2_e update bug (thanks to Sebastian Leist). 
2012/07    changed to mclustBIC in vblpcmstart function for compatibility with mclust 4. 
