Cleanup command line argument parsing & installation

[hydrogen18]

I had some issues with the program crashing and other problems. I made a number of changes here to address those:

1. Install to /usr/local/bin. For programs not from the package manager on a linux machine this is the normal location.
2. Avoid use of atof for parsing command line arguments. Use strtof instead. Check this result and if it isn't valid just terminate the program with an error. This prevents crashing the raspberry pi when an incorrect command line argument like 'bananas` is passed for the frequency arguments
3. Normalize arguments between the two programs
4. Use a boolean flag to check if ppm has been set. Otherwise use ntp to try and determine the correct ppm