adding ufs_srweather_app initial CMakeLists.txt file, and adding build summary

[edwardhartnett]

Part of #5

In this PR I add the initial CMakeLists.txt file. At the moment it does nothing except generate and print the build summary, but eventually it will do the build. ;-)

The build summary is implemented with a ufs_srweather_app.settings.in file. This file contains lines like this:

SRWA Version:		@SRWA_VERSION@
Configured On:		@CONFIG_DATE@

The fields inside '@" are substituted by cmake. So in our CMakeLists.txt file we have:

# Set extended version info.
SET(SRWA_VERSION_MAJOR 1)
SET(SRWA_VERSION_MINOR 0)
SET(SRWA_VERSION_PATCH 0)
SET(SRWA_VERSION_NOTE "-development")
SET(SRWA_VERSION ${SRWA_VERSION_MAJOR}.${SRWA_VERSION_MINOR}.${SRWA_VERSION_PATCH}${SRWA_VERSION_NOTE})

This results in the following in the settings file shown below. Note that the version info has been substituted into the file:

# UFS Short Range Weather App Configuration Summary
===================================================

# General
---------
SRWA Version:		1.0.0-development
Configured On:		Fri May 15 05:28:30 MDT 2020
Host System:		        x86_64-Linux-5.3.0-51-generic
Build Directory: 	        /home/ed/ufs-srweather-app/build
Install Prefix:                   /usr/local

# Compiling Options
-------------------
C Compiler:		/usr/bin/cc
CFLAGS:			 
CPPFLAGS:		 
LDFLAGS:		 
Shared Library:	no
Static Library:		yes
Extra libraries:	

# Features
----------
Parallel Support:	no

The settings file generated by CMake is called ufs_srweather_app.settings. It is for human use.

There is also a ufs_srweather_app_meta.h file produced, for the use of other programs to understand the build. This file is also automatically generated by CMake. It looks like this:

/*
 * Meta information for ufs-srweather-app which can be used by other
 * packages.
 *
 * This file is automatically generated by the build system
 * at configure time, and contains information related to
 * how ufs-srweather-app was built. It will not be required to
 * include this file unless you want to probe the capabilities
 * of the build. 
 *
 */

#ifndef UFS_SRWEATHER_APP_META_H
#define UFS_SRWEATHER_APP_META_H

#define SRWA_VERSION_MAJOR 1 
#define SRWA_VERSION_MINOR 0 
#define SRWA_VERSION_PATCH 0 
#define SRWA_VERSION_NOTE  "-development"

#define SRWA_VERSION       "1.0.0-development"

#define SRWA_HAS_PARALLEL  0 
#endif