1.12.1: small fixes, language and version checker improvements

• Fixed a NullPointerException when drop-with-any-death is enabled.
• Fixed /withdraw not allowing values below 1.
• Improved language-related features.
  • Fixed languages not being recognized on first run.
  • Improved language handling.
  • Dutch language has been updated to fully support all messages.
  • Does not send warnings by default anymore when using another language than English.
• Improved available update-information, also at /coins update.