Ally Switch

[DizzyEggg]

Fixes #273

It's almost the oldest open issue and the last not done move effect from Generation5(well except Pledge moves). It's not an understatement to say it's a historic PR.

Potential for things to break: moderately high
Some testing before merging would be nice.

Animation(Psychic BG + variation of Double Team):

[AlexOn1ine]

If you use Ally Switch with both mons, The second mon goes seemingly for a random move and according to bulbagarden the second ally switch should just fail.

ally_switch.mp4

Some things that are missing

• If a Pokémon targeted an ally with a move, but as a result of Ally Switch the Pokémon is now targeting itself when it would execute the move, the move will fail
• Snipe Shot and the Abilities Stalwart and Propeller Tail ignore Ally Switch and hit the intended target.
• Using Ally Switch consecutively now decreases the chance of success for each consecutive use. Ally Switch will fail when used successfully by another ally Pokémon on the same turn.

Source

[DizzyEggg]

@AlexOn1ine

PR updated and ready to merge:

• as a result of Ally Switch the second mon goes seemingly for a random move - fixed + test
• Snipe Shot and the Abilities Stalwart and Propeller Tail ignore Ally Switch - fixed + test
• If a Pokémon targeted an ally with a move, but as a result of Ally Switch the Pokémon is now targeting itself when it would execute the move, the move will fail - fixed + test
• Using Ally Switch consecutively now decreases the chance of success for each consecutive use - fixed(with a config) + test
• Ally Switch will fail when used successfully by another ally Pokémon on the same turn. - not implemented! I actually checked it on Showdown, and the move did not fail. I usually trust Showdown more than Bulbapedia, so I decided to leave it as it is.

Note: better squash this PR when it gets merged, the history is a bit messy

[AlexOn1ine]