Make the eigen C files part of the common sources

Bug Fix: After the previous commit, the output was not correct for the OpenCL backend because it uses the shadow strand size rather than the original strand size. Fixed 

  Factored out common part of Diderot_World_t struct (see Diderot/world.h) and
  fixed output routines for the C and Parallel targets.

  Deal with the different sizes of status flags statically, instead of dynamically.

  Fix compiler warnings

Update includes a working version of the OpenCL backend and output support. Upated the output function args to include a size_t output argument for the output data. 

  minor code cleanup

  Switched parallel runtime to use Diderot_Output and Diderot_Print.  Also fixed a bug
  in nrrd output code.

  Split output code into two functions: one for nrrd files and one for text files.

  Added comments and fixed indentation

Moved output proceedure to seperate file and updated c-target to use new output.

  fix calculation of image size in bytes

  Add shadow types for marshalling data to the GPU

  Added timing support and fixed a build typo

  Working on OpenCL support

  expand tabs to avoid editor differences

  Adding support for command-line arguments

  Working on command-line option support

adding more comments, and cosmetic tweaks

incomplete commit of the previous bugfix

fixed hest-related memory bug triggered anytime that struct Diderot_Options_s's optDef_t *odef array had to be re-allocated. Basically: you can't give hest a pointer (to store a variable in) that points into an array that might be reallocated later, since the reallocation will end up at a different address

working implementation of hest wrappers for command-line arguments

  Reclaim space for option descriptors

  Added hest wrappers

  Split input functions into their own file and added Diderot_InputVec2

  Use double precision to compute transforms for images.  We then convert these to the
  target precision.

  Working on new runtime build infrastructure