Clean up --list-plugins output a bit

Indenting output, log empty directories, no-plug directories, etc.
Welcome message should be logged to info
Add new option --max-time
Only abort processing if it would last forever

With instruments, they can technically have an audio source, a MIDI source,
both, or neither. Now MrsWatson should detect only cases where there is no
valid source, thus causing processing to occur forever.
Clarify help for --color-test
Initial support for --config-file option
More error checking when adding program options
Minor cleanups to header, add documentation
Internal mrs_passthru plugin supports --display-info
mrs_passthru didn't define a prepareForProcessing
Application test case for mrs_passthru
Add new internal plugin: mrs_silence
Improve help text a bit
Remove unused function

It worked, but the less code, the better.
Rename to pythonish self, add documentation
Add function to flatten LinkedList to array

Man, I've been needing this for a looong time, not sure what took me so long
to write this fairly trivial code.
Disable argument if it could not be filled during parsing
Don't rely on stupid variable recycling
Implementation of programOptionsParseConfigFile
Remove test files when test finishes