Implement XY Battle Spot Doubles

This commit also introduces the 'Standard GBU' ruleset, which bans Dark
Void, Soul Dew, and the many banned legends in VGC and GBU
Fix ability for Scizor when selected as Scizor-Mega

Technician used to be replaced by Swarm
Merge pull request #458 from V4Victini/formats

Implement XY Battle Spot Doubles
Fix egg group names to Field and Grass
Sync learnsets
Merge pull request #459 from Slayer95/patch-1

Fix ability for Scizor when selected as Scizor-Mega
Fix egg group names to Amorphous and Human-like
Fix egg groups to Undiscovered and Human-Like
Fix Mewtwo X Stats
Merge pull request #460 from Layell/patch-1

Fix Mewtwo X Stats
Fix hidden abilities being allowed in Gen 3 & 4
Also fix hidden ability for Flygon in NEXT
Fix Megamewtwo (X and Y) being allowed in Pokebank
Fix lack of item being banned in Gen 6 Uber tiers
Merge pull request #463 from Slayer95/patch-1

Fix lack of item being banned in Gen 6 Uber tiers
Merge pull request #462 from Slayer95/patch-1

Fix Megamewtwo (X and Y) being allowed in Pokebank
Merge pull request #461 from Slayer95/master

Fix hidden abilities being allowed in Gen 3 & 4
Merge remote-tracking branch 'upstream/master'