Welcome Message Reloaded

· [~] Clarified documentation and configuration. · [~] Color replacement in placeholders of PlaceholderAPI.

· [+] Added the possibility to remove default join message. · [~] Clarified documentation and configuration.

· [+] Added delay for each type of message · [+] Code optimization · [+] Added the possibility to choose to send the welcome message only the first time, except the first time or both. · [~] Better handling of PlaceholderAPI.

· [+] Support of PlaceholderAPI · [+] Registering permissions · [-] Old placeholder system

· [+] Messages, titles and sounds can now be send after each connection if enabled.

· [~] Welcome message should be sent after the join message · [~] Edit default config.yml for a better default usage · [~] Change volume and pitch to be double · [+] Author in plugin.yml