Option/flag processing

Added some option/flag processing functionality - currently just -h
(print help message and quit) and -devrpt (print report used for
development/debugging, which currently displays all valid state
transitions).
Minor cleanup of option-processing logic

Changed option-processing logic so that if the -h option is given
midifilter displays the usage message and exits without any other error
or warning message (such as warning about an empty configuration file).
Added basic installation instructions.