#20 2 identical GPS tagged photos disappear on map with regroup

[a1g0rithm]

If you have 2 photos in an album with the same GPS cord. the photos will disappear from the map view with "automatic item regroup" on.

Steps to reproduce:

- create album
- add gps photo1
- verify marker shown on album map
- add gps photo2 (different)
- verify 2 markers shown on album map
- turn on "automatic item regroup"
- verify 2 markers shown on album map
- add second copy of gps photo1 to album
- verify only 1 marker shown on album map (photo2)
- turn off "automatic item regroup"
- verify 2 markers shown on album map

Currently using 0.5.5
(tried svn version as well)