Added reset for pitch/yaw if they are somehow set to NaN.

src/main/java/net/minecraft/server/Entity.java

@@ -147,7 +147,12 @@ public abstract class Entity {
 
     protected void c(float f, float f1) {
         // Craftbukkit start
-        if ((f == Float.POSITIVE_INFINITY) || (f == Float.NEGATIVE_INFINITY) || (Float.isNaN(f))) {
+        if (Float.isNaN(f)) {
+            // CraftBukkit - yaw was sometimes set to NaN, so we need to set it back to 0.
+            f = 0;
+        }
+
+        if ((f == Float.POSITIVE_INFINITY) || (f == Float.NEGATIVE_INFINITY)) {
             if (this instanceof EntityPlayer) {
                 System.err.println(((CraftPlayer) this.getBukkitEntity()).getName() + " was caught trying to crash the server with an invalid yaw");
                 ((CraftPlayer) this.getBukkitEntity()).kickPlayer("Nope");
@@ -155,7 +160,12 @@ public abstract class Entity {
             f = 0;
         }
 
-        if ((f1 == Float.POSITIVE_INFINITY) || (f1 == Float.NEGATIVE_INFINITY) || (Float.isNaN(f1))) {
+        if (Float.isNaN(f1)) {
+            // CraftBukkit - pitch was sometimes set to NaN, so we need to set it back to 0.
+            f1 = 0;
+        }
+
+        if ((f1 == Float.POSITIVE_INFINITY) || (f1 == Float.NEGATIVE_INFINITY))  {
             if (this instanceof EntityPlayer) {
                 System.err.println(((CraftPlayer) this.getBukkitEntity()).getName() + " was caught trying to crash the server with an invalid pitch");
                 ((CraftPlayer) this.getBukkitEntity()).kickPlayer("Nope");