2012-12-16 Albart Coster <albart@dairyconsult.nl>
	* Function read.IPGPedigree is removed, this was a function to
	read a very specfic pedigree file.
	* Function errors.ped is removed, the code of this function is now
	included in function orderPed.
	* Function orderPed now checks for errors in the pedigree. Easy
	errors, which previously could be controlled with function
	errors.ped are detected (duplicate animals, animals with two
	sexes). Loops in the pedigree will not cause crashes anymore but
	will be reported to the user. The user remains responsible for
	identifying and solving these errors.