As Suggested by Alex-0000, migrated from DBCP to HikariCP (uses less
external JARs and got a cleaner code overall). Fixed some issues
regarding pets, such as evolving or hatching from egg. Added dojo skills
and fixed energy bar. Added missing upgrade books on drop data.
Implemented EXPERIMENTAL DBCP (connection pool), trying to improve
concorrent access to DB. Added door portals on Kerning Square. Fixed
equipments getting stat overflow when upgrading stats. Fixed expiring
pets crashing the client in some cases.
Added mechanics for the EXP/DROP cash coupons (such as enabling
out-of-time active coupons via command and automatic update of active
ones over the designed interval). Created MapleCouponInstaller as means
to gather info about the coupon intervals and rates from the WZs (the
generated SQL table is already updated on the db_database.sql file).
