CMake build of diffwrf binaries

[islas]

TYPE: enhancement

KEYWORDS: cmake, diffwrf

SOURCE: internal

DESCRIPTION OF CHANGES:
Problem:
New CMake build did not create binaries for io_* diffwrf

Solution:
Slight restructure of certain targets to allow for easy creation of the diffwrf executables. Since previously all diffwrf binaries were named the same, to house them int the same install/bin/ location they have been prefix with the type of io or shorthand of that option ( io_int -> diffwrf_int, io_netcdf -> diffwrf_nc, io_netcdfpar -> diffwrf_ncpar ).

LIST OF MODIFIED FILES:
M CMakeLists.txt
M external/io_int/CMakeLists.txt
M external/io_netcdf/CMakeLists.txt
M external/io_netcdfpar/CMakeLists.txt

TESTS CONDUCTED:

1. Diffwrf execs should now be located in cmake install location

RELEASE NOTE:
CMake build of diffwrf binaries

[weiwangncar]

@islas I haven't received reg test report from this PR either.

[weiwangncar]

@islas I haven't received reg test report from this PR either.

@islas It's possible that since this PR only changes .txt files, and no tests are triggered.
@mgduda Can you review this PR, please?