[SoC] r.sun: Now Available in OpenCL!

[Seth Price]

Hey all, good news! I now have r.sun written to run in OpenCL in GRASS  
7. My test shows a 20x speedup over the original code. ("r.sun  
numpartitions=3 elevin=gauss glob_rad=glob_rad_ocl day=180")

Feel free to download the code from here:
http://github.com/mailseth/OpenCL-integration-for-GRASS---GDAL

It's currently setup for compiling on my machine, a Mac. You'll need  
to play with the makefile to get it to work otherwise.

I've only done limited testing, so if you find something that makes it  
error, please send a helpful bug report my direction. You could also  
send me a data file and the exact commands needed to replicate the  
problem.
~Seth