* Update in NeuralNetLearner function

* made the changes as suggested

* no need of if else

* no need of if - else .   

As if hidden_layer_sizes is zero then it will not affect layer_sizes

* removed comment

* Update learning.py

* update in multimap functi n in utils.py and added test for it

* made changes according to PEP style

* broke the long sentence to 2 shorter sentences

* updated the sequence function and added test cases

* updated according to the PEP style

* improved the count function in utils.py

* updated according to PEP style

* added some test cases to first function in utils.py

* added space after each comma

* Fix typos for Wupus agent

* fix imports

`usa` in csp.py incorrectly has NM not being a neighbor with AZ.

Otherwise `csp.curr_domains` may not be available for the loop that follows.

Shortened it, finding conflicts separately and storing them in different variables has no use later in the notebook; so i believe this looks better.

Corrected typos + minor other text changes

Typos and minor other text errors removed

Made a colored table to display dog movement instead. Corrected grammatical errors, improved the sentence structure and corrected any typos found.

* Revamped the notebook

* A few changes reversed

Changed a few things from my original PR after a review from ad71.

A thank you to contributors from the GSoC 2018 program!

`self.heap.append` simply appends to the end of the `self.heap` 
Since `self.heap` is just a python list. 
`self.append` calls the append method of the class instance, effectively putting the item in its proper place.