segtest 2.0.0

• seg_lrt(): Tests for segregation distortion for arbitrary (even) ploidy F1 populations.
• seg_multi(): Runs seg_lrt() at many loci, with parallelization support from the future package.
• gamfreq(): Gamete frequencies under various models of meiosis.
• gf_freq(): Genotype frequencies of an F1 population under various models of meiosis.
• drbounds(): Two different upper bounds on the double reduction rates.
• beta_bounds(): Two different upper bounds on double reduction adjustment for simplex loci.
• n_pp_mix(): Number of mixing components in the pairing configuration model for partial preferential pairing.
• Added a NEWS.md file to track changes to the package.