NCDF library to v4

I changed the supported NetCDF library to use the ncdf version 4 library. This adds support for compressed NetCDF files, which I've started using for WILMA so we don't have to try and sling around 2TB of model output (compressed, they average 20MB instead of 500MB).

The only disadvantage to this is that the ncdf4 library in CRAN only has direct support for MacOS and Linux. The Windows version is available, but only for 32-bit R. I've added a "lib" directory and included that compiled version and updated the README to help the uninitiated. 

-Luke