Strip sRGB profile in PNG images

Hello!

PgAdmin built with wxWidgets 3.0 under Windows gives following warning
messagebox on startup (twice):

12:41:22: Warning: iCCP: known incorrect sRGB profile

After that the application works normally. As discussed here
https://bbs.archlinux.org/viewtopic.php?pid=1269845
warnings are triggered by new version of libpng.
A test with imagemagick's identify *.png points to problematic images:

pgadmin/include/images/resourcegroup.png
pgadmin/include/images/resourcegroups.png

Attached are these images "convert"ed to strip sRGB profile. Please
commit them.

--
Best regards,
 J.F.