shared_ptr -> std::shared_ptr

This is one of the first commits in a plan to remove all `using namespace std;` lines in the entire codebase as it is considered anti-pattern today.

Minecraft.World/ExperienceOrb.cpp

@@ -187,7 +187,7 @@ void ExperienceOrb::readAdditionalSaveData(CompoundTag *tag)
 	value = tag->getShort(L"Value");
 }
 
-void ExperienceOrb::playerTouch(shared_ptr<Player> player)
+void ExperienceOrb::playerTouch(std::shared_ptr<Player> player)
 {
 	if (level->isClientSide) return;
 
@@ -258,7 +258,7 @@ int ExperienceOrb::getIcon()
 * Fetches the biggest possible experience orb value based on a maximum
 * value. The current algorithm is next prime which is at least twice more
 * than the previous one.
-* 
+*
 * @param maxValue
 * @return
 */