Create the retrms array explicitly as an Any array, fixing the gliches encountered earlier.
Merge branch 'master' of git://github.com/dmbates/MixedModels.jl

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csc_symperm renamed to symperm.  Import from Stats instead of GLM when possible.
Store LambdatZt as SparseMatrixCSC.  Store fnames.
Improve print method.
Correct the fnames method.
Modifications in basic logic for constructing Zt.  Still not correct.
Add an fnames method.