Use `canMegaEvo` flag.

The server will tell us what we can and cannot Mega-Evolve
Readd previous condition

Backwards Compatibility
Merge pull request #113 from V4Victini/patch-19

Use `canMegaEvo` flag.
Don't crash on !data in replays
Update teambuilder for gen 6 tiers
Merge branch 'master' of github.com:Zarel/Pokemon-Showdown-Client
Make PM windows minimizable
Merge pull request #114 from Quinella/minimize-pm

Make PM windows minimizable
New Player rank
PM minimizing: change color of PM header for new messages
Also fixed some CSS rules to be consistent with the other rules