Moved throw pos and speed calculation from cProjectileEntity into cPlayer.
Basic support for thrown items - eggs, snowballs and ender pearls.

They can be thrown, but they don't do anything on impact. Also they don't save to nor load from  MCA.
AnvilStats: Ignoring the build folders
AnvilStats: Added the callback for region begin and end.
AnvilStats: Callbacks can now use CALLBACK_CONTINUE and CALLBACK_ABORT instead of bool return values.

This makes the code slightly easier to understand.
AnvilStats: Implemented a cImageComposingCallback class.

This will ease the creation of callbacks that produce per-region images of stuff.
Merge branch 'Projectiles'