tweaks to entity API code

src/main/java/carpet/fakes/LivingEntityInterface.java

@@ -0,0 +1,7 @@
+package carpet.fakes;
+
+public interface LivingEntityInterface
+{
+    void doJumpCM(); // added CM suffix to remove potential collisions with other mods
+    boolean isJumpingCM();
+}