Merge pull request #2 from EmilHernvall/master

Merge from master
Ridden horses now teleport with you when using /tp
Ridden horses now teleport when using /spawn
Ridden horses now teleport when being summoned
Merge pull request #3 from EmilHernvall/master

Merge from master
Merge pull request #17 from sabersamus/master

Various horse fixes