JSHint is now a fair bit stricter, and is now correctly checking
files in `mods/`.
The code has been fixed to match the new stricter standards.
JSHint has now caught its second actual bug: Gen 5 Pinap Berry
was Ice instead of Grass.
During initialisation of Tools, each new mod no longer makes a copy
of every data object from the parent mod. Instead, a new object is
created when and only when the mod actually makes changes to a
particular object. In other words, this is a "copy-on-write" system.
