WebPlugin: Make it clear where this logging statement is coming from
Documentation updates
NancySample: rename Watch to StartRunner

- Name doesn't matter, but StartRunner is more descriptive
Watcher: tried to implement support for watching subdirectories, but a FileSystemWatcher issue stopped me

- Could just manually add all the subdirectories to the watcher, but without filtering, this can be a lot more than I bargained for (may be inefficient)
- Updated docs to indicate that subdirs should be watched explicitly
Documentation: small tweak