Unique Release Number Implementation

To see if the git command is available, a find_program command was added to the CMakeLists.txt file, which sets the CMake variable PROGRAM_GIT.  An if command was also added that checks if this variable is set, which then executes the command using the  execute_process command for the describe sub-command in the project source directory setting the CMake variable ibcp_RELEASE_STRING with the resulting string.  The option OUTPUT_STRIP_TRAILING_WHITESPACE was needed to remove the trailing newline.

If the git program was not found, then the ibcp_RELEASE_STRING variable is set to "v" followed by the major and minor release numbers separated by a period.  If the patch release number is less than zero (development tag), then the patch number is appended to the release string (the dash is present because the number is negative).  Otherwise, the patch number is appended with another period separator.  The final release string, from either source, is output to the CMake output log.

In implementing this if command, it was realized that it was not necessary to test the PROGRAM_GIT variable for the string to be equal to "PROGRAM_GIT‑NOTFOUND" as was done with the awk program because this is one of the tests performed by the CMake if command.  Therefore, the if command for the awk program was simplified.

A define for ibcp_RELEASE_STRING was added to the ibcp_config.h.in file (used to auto-generate ibcp_config.h) with the contents of the CMake variable surrounded by quotes, to form a string constant that can used in the source code.  The ibcp_version() function was modified to output this string constant instead of the major, minor and patch numbers.  The "v" part of the string is not output (because "version" is already being output).  Finally, the GPL header was removed when outputting the version number to be consistent with the output of other programs.

New branch0.2 was created.  The release string produced at this latest commit will be v0.1.16b-1-g1bba2c3, which shows the most recent tag (v0.1.16b), the number of commits beyond this tag (1) and the short commit ID (1bba2c3).  The "g" in front of this ID stands for git (other letters would stand for other software configuration management systems).

[commit 1bba2c335c]