Make context work less-disruptively

They should be their entirely own system, really... but this'll do for
now.

src/main/java/net/aufdemrand/denizen/scripts/ScriptBuilder.java

@@ -26,8 +26,8 @@ public class ScriptBuilder {
      */
     public static List<ScriptEntry> addObjectToEntries(List<ScriptEntry> scriptEntryList, String key, Object obj) {
         for (ScriptEntry entry : scriptEntryList) {
-            entry.addObject(key, obj);
-            entry.trackObject(key);
+            entry.addObject("context_" + key, obj);
+            entry.trackObject("context_" + key);
         }
         return scriptEntryList;
     }

src/main/java/net/aufdemrand/denizen/tags/core/ContextTags.java

@@ -64,7 +64,7 @@ else if (type.equalsIgnoreCase("NAME")) {
     public void getContext(ReplaceableTagEvent event) {
         if (!event.matches("context, c") || event.getScriptEntry() == null) return;
 
-        String type = event.getType();
+        String type = "context_" + event.getType();
 
         // First check for entry object context
         if (event.getScriptEntry().hasObject(type)) {