Babys can merge migration waves

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What steps will reproduce the problem?
1. Group by Migration wave
2. have a fort with many pregent dwarves
3. have new babies in less than 28 Days (33600 tics) 
   between the last migration wave or the last baby born
   till the next wave arrives.  

What is the expected output? 
see distinct migration waves 

What do you see instead?
some migrations waves are merged together

The new methode to calculate the migration wave   
(Issue 382 http://code.google.com/p/dwarftherapist/issues/detail?id=382 
http://code.google.com/p/dwarftherapist/source/detail?r=1d7c70a6b50c8d24545c1082
383ac28440973600 )
puts a dwarv in the same migration wave as the dwarf befor
if he arrives withhin wave_gap=33600 tics (28 Ingame Days). 

The value for wave_gap is so large, that it is possible to merge
to migration waves if there are some babies in between.
Reducing wave_gap to somthing between 1200 (1 Day) and 6000 (5 Days)
will seperate the waves. 

Original issue reported on code.google.com by kelewan...@gmail.com on 23 Apr 2012 at 8:31

[GoogleCodeExporter]

even wave_gap=6000 is to big in some forts. So far wave_gap=1200 works fine, 
but it might be good to make this a configuration option 

Original comment by kelewan...@gmail.com on 14 May 2012 at 7:15