Merged updates to regexp_nodes from our production fork

• Cleaned up examples to reflect reality and be less snarky
• Renamed example parameter to 'service' so it doesn't overlap with reserved word 'environment'
• Figure out where we live using Pathname.realpath
• Change logging to use syslog instead of hardcoded log file
• Handle comments and whitespace in pattern files gracefully
• Skip over dotfiles in pattern directories