src/img.c,src/img.h,src/mainfrm.cc: Store the 'processed at'
timestamp in the .3d file as seconds since 1970 rather than as
a human readable string.
tests/: Commit files for new tests.
lib/Makefile.am,lib/merge-po: Add "merge-pos" target to merge in new
messages and updates to comments from survex.pot to the .po files.
lib/: Update line number references and merge message changes from
survex.pot to the .po files.
* .gitignore,src/gen_img2aven: Commit script to generate img2aven.h.
src/mainfrm.cc: Fix mapping of flags when loading a .3d file.
src/img.c: Handle .pos files containing unnamed stations - don't suck
the next line in as the station name, and set img_SFLAG_ANON for
them.