Move exceptions to their own package.

This will break plugins that directly catch these exceptions.

src/main/java/com/gmail/nossr50/api/ExperienceAPI.java

@@ -4,6 +4,8 @@ import java.util.Set;
 
 import org.bukkit.entity.Player;
 
+import com.gmail.nossr50.api.exceptions.InvalidPlayerException;
+import com.gmail.nossr50.api.exceptions.InvalidSkillException;
 import com.gmail.nossr50.config.Config;
 import com.gmail.nossr50.datatypes.player.PlayerProfile;
 import com.gmail.nossr50.datatypes.skills.SkillType;

src/main/java/com/gmail/nossr50/api/InvalidPlayerException.java → src/main/java/com/gmail/nossr50/api/exceptions/InvalidPlayerException.java

@@ -1,4 +1,4 @@
-package com.gmail.nossr50.api;
+package com.gmail.nossr50.api.exceptions;
 
 public class InvalidPlayerException extends RuntimeException {
     private static final long serialVersionUID = 907213002618581385L;

src/main/java/com/gmail/nossr50/api/InvalidSkillException.java → src/main/java/com/gmail/nossr50/api/exceptions/InvalidSkillException.java

@@ -1,4 +1,4 @@
-package com.gmail.nossr50.api;
+package com.gmail.nossr50.api.exceptions;
 
 public class InvalidSkillException extends RuntimeException {
     private static final long serialVersionUID = 942705284195791157L;