Balances, small bug fix, and new artifact.

- Made 'Spike Ball' collision slightly larger. - Made 'Mace' range larger. - Made 'Travel East' and 'Obelisk' missions slightly easier. - Made 'Revolver', 'Knife Throw' and 'Sniper' stronger, made 'Axe' a bit more faster with levels. - Made 'Whip' more visible. - Fixed bug that showed 'Horse' in the mounts menu, even though its not possible to buy. - Removed 'Obelisk' from boss kill stats. - Added artifact: 'Decoy'.