Switching monitors to use threads over processes to resolve issue with zombie processes and related errors

Also, added a pause between monitor failure reattempts to allow for potential network interruptions, service restarts, and other factors that could cause connection issues.
Updating service setup to include directory change to $LR_HOME required for proper LR startup
Adding a title to OAuth management page so one can find it amongst their open tabs
Updating LRSignature reference and version requirement
Fixes to replacement/tombstone code, added trusted public key whitelist for allowing deletions (#269)
Creating a mass_delete utility to easily send deletes by signer/submitter