Remove Ignore invalid Marker Icon ID's in maps

Spigot has patched this issue inside MapIcon, meaning that we no longer need to maintain this patch; Spigots patch also fixes #668 in that it will verify the length of the array, as well as protect against a negative type value being fetched from the array. Only real change is that Spigots patch returns a MapIcon.Type.PLAYER, instead of the RED_MARKER as originally PR'd by Aikar.

Spigot-API-Patches/0032-Add-MetadataStoreBase.removeAll-Plugin.patch

@@ -1,4 +1,4 @@
-From 804562f99c8f2bf6b5d9937d5a7816974c716502 Mon Sep 17 00:00:00 2001
+From 1a59075c01dbe0d53bd6fbfd94ccb1ef6a047a6a Mon Sep 17 00:00:00 2001
 From: Aikar <aikar@aikar.co>
 Date: Tue, 16 Jul 2013 21:26:50 -0400
 Subject: [PATCH] Add MetadataStoreBase.removeAll(Plugin)
@@ -6,7 +6,7 @@ Subject: [PATCH] Add MetadataStoreBase.removeAll(Plugin)
 So that on reload, metadata will be cleared
 
 diff --git a/src/main/java/org/bukkit/metadata/MetadataStoreBase.java b/src/main/java/org/bukkit/metadata/MetadataStoreBase.java
-index 64c0f0a..6da6abd 100644
+index 64c0f0a7..6da6abd8 100644
 --- a/src/main/java/org/bukkit/metadata/MetadataStoreBase.java
 +++ b/src/main/java/org/bukkit/metadata/MetadataStoreBase.java
 @@ -125,6 +125,26 @@ public abstract class MetadataStoreBase<T> {
@@ -37,5 +37,5 @@ index 64c0f0a..6da6abd 100644
       * unique data from the subject with a metadataKey.
       * <p>
 -- 
-2.9.2.windows.1
+2.12.2