populate-app: really support MacOSX
populate-app: really support MacOSX

Contrary to this developer's memory, BSD sed does not understand \t to
mean the TAB character.

Also, the ctimes of just unzipped files is not reliable on MacOSX, so
jump through hoops and really compare the files present with the files
that came from the .zip archive.

Signed-off-by: Johannes Schindelin <53fb8db7833fca1e1746dd8592f61048d350f64c@gmx.de>

biovoxxel/imagej,biovoxxel/imagej,TehSAUCE/imagej,TehSAUCE/imagej,TehSAUCE/imagej,biovoxxel/imagej