Aha, I hadn't spotted the `../examples/data/` trick, which I noticed also wasn't being done to set the paths to the PSF and Power Spectrum.  I've fixed this in the Python, YAML and JSON scripts for demo11, so the code now *almost* runs perfectly in both `examples/` and `bin/`... And I've removed the warning you didn't like.

I say almost above, because in testing within the `bin/` directory I've noticed that the following executables built there (e.g. `demo11*`, etc.) fail due to not having an `output/` subdirectory: `demo11*`-`demo5*`.  The executable `demo4*` fails when run from `bin/` due to a lack of an `inputs/` directory. 

I plan to simply fix all those up on this branch using `os.path.isdir` and `mkdir`... any objections?