-Added locks to all sync processes (blocks, markets, peers, masternodes) as well as "create backup", "restore backup" and "delete database" functions. This helps prevent problems with syncing data while a backup is in progress for example
-The code to initialize certain database collections on startup was moved into database.js and is now called from restore_backup.js and delete_database.js. This effectively allows the database to be deleted or restored to a completely different backup while the explorer is still running
-Lock functions (create_lock, remove_lock, is_locked) were moved into explorer.js for better reusability and rewriten to be synchronous
-is_locked function now accepts an array of lock files to be able to check for multiple locks in a single call
-remove_sync_message() function was moved into database.js so that restore_backup.js and delete_database.js can also check for and remove the sync msg if it exists
-Useful Scripts section updated in the README to make it clear that the explorer no longer needs to be stopped for these scripts to be run
-Most if not all log messages now start with a capitlal letter
Joe Uhren
d7c18a48f5