Add ability to remove keys from memory

q- remove() takes a list of keys to delete from memory.

donkeycar/memory.py

@@ -30,6 +30,9 @@ def __getitem__(self, key):
             return self.d[key]
 
     def update(self, new_d):
+        '''
+        update memory with values from a dictionary
+        '''
         self.d.update(new_d)
 
     def put(self, keys, inputs):
@@ -44,11 +47,18 @@ def put(self, keys, inputs):
         else:
             self.d[keys[0]] = inputs
 
-            
+        self.d.update(dict)
 
     def get(self, keys):
         result = [self.d.get(k) for k in keys]
         return result
+
+    def remove(self, keys):
+        '''
+        Remove all the keys in the given list
+        '''
+        for key in keys:
+            del self.k[key]
 
     def keys(self):
         return self.d.keys()