Added command to set a trekker's emblem stats

Usage:
`!e [character id] [slot id - this is between 1 and 3] [attr 1] [attr 2] [attr 3] [attr 4]`

Example:
`!e 141 1 1004 1004 1004 1004` = Sets the first emblem of the character to all +ignis damage.

Notes:
Attribute ids can be found in `CharGemAttrValue.json` in the resources/bin folder.

src/main/java/emu/nebula/game/character/CharacterGem.java

@@ -25,6 +25,10 @@ public class CharacterGem {
     public void setLocked(boolean locked) {
         this.locked = locked;
     }
+    
+    public void setAttributes(IntList attributes) {
+        this.attributes = attributes.toIntArray();
+    }
 
     public void setNewAttributes(IntList attributes) {
         this.alterAttributes = attributes.toIntArray();

src/main/java/emu/nebula/game/character/CharacterGemPreset.java

@@ -27,7 +27,9 @@ public class CharacterGemPreset {
         return this.getGems().length;
     }
     
-    public int getGemIndex(int slotIndex) {
+    public int getGemIndex(int slotId) {
+        int slotIndex = slotId - 1;
+        
         if (slotIndex < 0 || slotIndex >= this.getLength()) {
             return -1;
         }

src/main/java/emu/nebula/game/character/CharacterGemSlot.java

@@ -36,6 +36,10 @@ public class CharacterGemSlot {
         return getGems().size() >= GameConstants.CHARACTER_MAX_GEMS_PER_SLOT;
     }
     
+    public boolean isEmpty() {
+        return getGems().size() <= 0;
+    }
+    
     // Proto
     
     public CharGemSlot toProto() {