[GRASS5] file clones in imagery modules

[Hamish]

> what to do withh all the clones files in
> imagery/?


some things to look out for-

Some bug fixes and improvements have been made to i.rectify. Others to
i.photo.rectify. These were often not applied to both modules so the
best of the two would need to be combined.

Same goes for i.points and i.vpoints.



Now that GDAL is not optional, perhaps we should use the GDAL Warp API
with i.rectify as a front end. The code is from the same base, but
Frank's is better maintained and has more neat features (like thin plate
spline rectifications). Less stuff for us to needlessly maintain.


GDAL Warp API Tutorial:
  http://www.gdal.org/warptut.html


If a lot of effort is going to go into cleaning up i.rectify et al., it
would be nice if we could take the opportunity to use libgdal's existing
library functions instead of perpetuating our own slightly dusty ones.


Hamish