Remove group numbers when all available animals have been used

@return The grpNum list after removing any list element corresponding to a group with no available animals left using in filling a group.

removeGroupIfNoAvailableAnimals(grpNum, available)

Arguments

grpNum	as list of integer vectors initially populated with one list named by the integers 1:numGrp, where numGrp is the number of groups to be formed. Each list member is initially populated with a integer vector seq_len(numGrp).
available	is a list of numGrp named members and each member is initially defined as the character vector made up of candidate animal Ids.