Fixed an exploit in the custom jobmaster NPC

- Improved legibility (renamed variables, replaced numbers with
  constants.
- Changed syntax to match Hercules standards.
- Fixed status point exploit upon Baby Novice job change.
- Special thanks to bgamez23.

Signed-off-by: Haru <haru@dotalux.com>
Improved @go command

- Corrected checks to correctly display the help message when an
  invalid map name is requested (rather than warping to Prontera)
- Removed huge list of hardcoded town names (special thanks to KeiKun).

Signed-off-by: Haru <haru@dotalux.com>