Added Vector3::TurnCW() and Vector3::TurnCCW()
Refactored all player block placing to go through hooks.

Fixes #1618.
gcc compilation fix.
Replaced a std::hash specialization with explicit type.

std::hash is problematic in gcc / clang, one has a class, the other a struct.
ByteBuffer: SingleThreadAccessChecker is request-only.

It slows the server down way too much, so it can't be turned on by default.
Fixed redstone dust placement on upside-down slabs.
APIDump: Updated the player block placement documentation.

The hooks now have fewer parameters but are called on all player-placed blocks (#1618).
Merge pull request #1686 from mc-server/PlaceBlockRefactor

Place block refactor
cIsThread: Fixed a race condition on thread start.
APIDump: Added details about client handle in OnServerPing hook.
Fixed basic style.
Fixed forgotten big flower handler.
Fixed door placement.
Fixed tools compilation.

Fixes errors introduced in 081e7ddd028d9382bd52c2b117dae6b6f84225e5.
Added basic style checking to Travis builds.
Travis: Added lua installation before build.
Travis style check in the right folder.
Merge pull request #1687 from mc-server/StyleCheckTravis

Style check travis
MobHeads: fixed regular head placement.
ProtoProxy: Log block change packet details.