change (quick-)add algorithm

[westram]

Current behavior:

• sorts species by length (longest first)
• searches for best insert position (does one traversal for each inserted species)

Wanted behavior:

• try insert-positions for ALL species (to insert) in one traversal
• unique targets (i.e. positions where only one species has its best position) can be inserted right away
• other target position at which multiple species have their best insert position need to be optimized after all insertions were made

Expected effect: (dramatically) reduced number of performed combines

[westram]

by [15459]