The following changes were made to make the first reproducible arXiv
release (arxiv:1505.01664, v2). The major additions are:

  - The `--onlydirconf' option was added to the common options. When
    called, only the current directory configuration files are read
    (not the system or user wide configuration options). This will
    allow much easier control over what parameters go into the running
    of a program, which is very useful when reproducibility is
    concerned.

 - The `--onlyversion' option was added to the common options. When
   called, the version of the program is checked with the value to
   this option, and if they aren't exactly equal, the program will not
   run. This is crucial for reproducibility.

 - Added the READ_COMMONOPTIONS_FROM_CONF macro to configfiles.h to
   read common configuration options from a configuration file. Until
   now, there was only the `--numthreads' option, and each program had
   a step to read it, but with the new `--onlydirconf' option, it
   required now too much repetition to be read in each program
   independantly. So this macro was defined and is used by all the
   programs.

 - Added the macro PRINT_COMMONOPTIONS, similar to above, this is done
   to make things more clearer and remove bugs.

 - Added the `astrthreads.h' headers to `spatialconvolve.h' to avoid
   problems with systems that don't support pthread_barrier_t.

 - Added the `--mirrordist' option to ImageStatistics to set the
   maximum distance beyond the mirror.

 - Added the `--maxblankfrac' option to ImageWarp so if a large
   fraction of an output pixel is covered by blank pixels, it is set
   to blank. Before the blank fraction was ignored.