Add in-game flags to all moves

- To be used in a one by one refactor of all current flags across the
generations
Update all move descriptions
Make sure moves have the flags object
Update old moves to Gen 6 mechanics
Reject Head Smash with Sturdy

Donphan is mostly going to have Sturdy, so we also remove it from its move
set and replace it with some better stuff.
Nerf Articuno in Random Battles

Reduced to Level 82.
Update Balloon Fan Rotom (Rotom-Spin)

- Modified level scale so that it's less bad
- Removed Trick from its movepool because it's useless with Balloon
Update UU bans
Merge pull request #1370 from ascriptmaster/randoms

Some random battle updates (as suggested by PS staff)
Only show ac account if different from username
Update Random Battle

- Added moves to Cherrim
- Changed levels
Reject Rock Head with less than two recoil moves

in Random Battle
Make sure Nature Power targets correctly
Improve Seasonal with user suggestions

Improved the set maker to avoid bad sets due to Present.
Made the mountain 500 meters shorter.
Made the chance to hit an obstacle slightly lower.
Added weight to the sleigh that is lowered by throwing Presents and makes you faster.
Refactor bite, bullet, and pulse moves
Merge pull request #35 from Zarel/master

Patch 2.8