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Add options to control theta<-: make caching optional, make gradient
optional (again), use rel.tol?, make eps into an option
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Add option devFunOnly like lmer2
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Fix FIXMEs in Q("rlmerMod")
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Speed up Q using dense matrices
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Correct for correlation only after applying rho
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Improve summary for REML=FALSE: only show AIC, BIC, etc. if they really are that.
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Improve summary: title _Robust_
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Add missing documentation.
