Add two new hooks for the custom mutator

- `afl_custom_queue_get` and `afl_custom_queue_new_entry`
- Update the corresponding document and examples

examples/custom_mutators/example.py

@@ -120,3 +120,55 @@ def fuzz(buf, add_buf, max_size):
 #     '''
 #     return buf
 #
+# def havoc_mutation(buf, max_size):
+#     '''
+#     Perform a single custom mutation on a given input.
+#
+#     @type buf: bytearray
+#     @param buf: The buffer that should be mutated.
+#
+#     @type max_size: int
+#     @param max_size: Maximum size of the mutated output. The mutation must not
+#         produce data larger than max_size.
+#
+#     @rtype: bytearray
+#     @return: A new bytearray containing the mutated data
+#     '''
+#     return mutated_buf
+#
+# def havoc_mutation_probability():
+#     '''
+#     Called for each `havoc_mutation`. Return the probability (in percentage)
+#     that `havoc_mutation` is called in havoc. Be default it is 6%.
+#
+#     @rtype: int
+#     @return: The probability (0-100)
+#     '''
+#     return prob
+#
+# def queue_get(filename):
+#     '''
+#     Called at the beginning of each fuzz iteration to determine whether the
+#     test case should be fuzzed
+#
+#     @type filename: str
+#     @param filename: File name of the test case in the current queue entry
+#
+#     @rtype: bool
+#     @return: Return True if the custom mutator decides to fuzz the test case,
+#         and False otherwise
+#     '''
+#     return True
+#
+# def queue_new_entry(filename_new_queue, filename_orig_queue):
+#     '''
+#     Called after adding a new test case to the queue
+#
+#     @type filename_new_queue: str 
+#     @param filename_new_queue: File name of the new queue entry
+#
+#     @type filename_orig_queue: str
+#     @param filename_orig_queue: File name of the original queue entry
+#     '''
+#     pass
+