Added compareTo method for easier comparison in expasions.

src/main/java/me/clip/placeholderapi/expansion/Version.java

@@ -20,7 +20,7 @@
  */
 package me.clip.placeholderapi.expansion;
 
-public class Version {
+public final class Version {
 
   private boolean isSpigot;
 
@@ -38,4 +38,9 @@ public class Version {
   public boolean isSpigot() {
     return isSpigot;
   }
+
+  public boolean compareTo(String version) {
+    return getVersion().equalsIgnoreCase(version);
+  }
+
 }