qtl2cmst: Set up data for cmst function
In byandell/CausalMST: Causal Model Selection Hypothesis Tests

Set up R/qtl cross object and identifiers for use with cmst. The pheno and cov arguments must be valid names of cross$pheno. The Q.chr must be a valid chromosome identifier for cross.

1 2	qtl2cmst(cross, pheno1, pheno2, Q.chr, Q.pos, addcov1 = NULL, addcov2 = NULL, intcov1 = NULL, intcov2 = NULL)

`cross`	object of class cross; see `read.cross`.
`pheno1`	first phenotype name
`pheno2`	other phenotype names to test with `pheno1`
`Q.chr, Q.pos`	chromosome name (character) and position (in map units).
`addcov1, addcov2, intcov1, intcov2`	additive and interactive covariates for `pheno1` and `pheno2`.