segregatr 0.4.0

Liability classes are now supported also in looped pedigrees.
Fixed bug in the startdata construction which potentially allowed impossible input.
Added CITATION file, and links to shinyseg and papers.

segregatr 0.3.0

Added Christian Carrizosa as collaborator.
Depend on R 4.1 and pedtools v2.2.0.
FLB() now handles pedigrees with loops.
FLB() now handles recessive models (AR and XR) and homozygous carriers.
plotSegregation() now produces sensible default margins in most cases.
plotSegregation() has new arguments pos.geno and pos.arrow for alternative placements of genotype symbols and proband arrow.
Added several new examples and tests.
General code updates and improved organisation.