Multiple !place entries, timezone fixes

• Multiple places can now be entered with a single !place command. A carriage return should be between them, so they can be copy and pasted from a text editor for example.
• Time zones should now be handled properly with the !start command
• !start command entries can be overwritten by the user who originally added the start time.
• Fixing issue where 12 hours would be incorrectly added to the raid time.