Added vendor CREFL C code. Modified their directory structure so it had less cruft.
Updated cviirs.c to v2.0
Updated cviirs.c to v3.0
Updated cviirs.c to v3.1
Updated cviirs.c to my patched version of v3.1. This fixes the bug where SDR fill values were ignored.
Made a Makefile to make compilation/installation of CREFL much easier.
Bash scripts still need work so that they work either generically or with POLAR2GRID_HOME environment variable.