Focus: Add the Focus on Pokérus cure feature

[Farigh]

This feature will automatically move to routes were there is at least one infected pokémon that is not resistant to the pokérus. It will equip the set pokémon catching pokéball and catch every pokémon on that route until the full route is resistant. It will then move to the next route.

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Misc: improve interval delay

Always call the method once for long delay to avoid the feature lag impression.

Always call the method AFTER the interval setting to avoid side effects.

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Focus: Fixup some element naming to match accessibility

Some internal data/function were accessed by other focus sub-classes.

The __internal part of those element was removed

Partially adresses #122

[jensver]

Is it possible to add an option to skip alternate forms for Focus.PokérusCure? After doing all the Kanto routes, he switches to Pinkan pokemon.