get.logl: Calculate the log-likelihood
In drvalle1/EcoCluster: Bayesian Clustering using Truncated Stick-Breaking priors

This function calculates the log-likelihood based on the current parameter estimates

1	get.logl(y, omega, nspp, nloc, xmat, betas, cs, alpha)

`y`	L x S matrix, with the presence-absence data
`omega`	L x S matrix with the underlying latent variables omega
`nspp`	overall number of species (S)
`nloc`	overall number of locations (L)
`xmat`	L x P design matrix containing the covariates (columns) for each location (rows). Notice that this matrix does not contain a column of 1's for the intercept
`betas`	P x KS matrix containing slope parameters for each covariate (row) and each group (column)
`cs`	vector of length S wth group assignment for each species
`alpha`	vector of length S with intercept for each species