updated for change in git tag naming conversion

the naming convention of tags was changed from releaseX.X.X to vX.X.X,
which required the similar change to the creation of the version string
in CMakeLists.txt

the version function in the command line class that extracts the version
number from the version string creation of the version string for output
was updated to look for the first digit in the version string instead of
simply skipping over the first so many characters