V 2.1.5 - Simulator, analysis and bug fixes. (#167)

* create a tub for training against stack of N records through time

* joystick doc fixes

* added sdsandbox integration. testing time stack.

* specify keras and tensorflow version for linux desktop install

* added donkey sim integration

* added deps to setup.py

* added simulator docs

* create a movie from a tub

* improve error handling and usage for making movie from tub

* added docs for donkey commands

* use config instead of magic num

* fix sim steering scale. added steering plot analysis.

* rename movie command to makemovie

* smaller increment on delta max throttle

* more comments. added steer scale param

* add plot_predictions method to template

* no scale by default from sim server

* fixed linear model, added cropping and image norm

* add unit test for sim server

* document PID controls

* keep wanting to turn verbose off. added now as argument to train, along with others. default to on, as before.

* added linux joystick setup guide for simulator

* move sim command from manage.py to donkey command line utils

* A tricky bug that causes the cache of generator results

* command line arg for caching training data

* default to cache on. fix gether tubs

* rename analyze to histogram. added needed pandas dependancy for plot

* move gather tubs to tools and added tests. Added docs for plot_predictions and histogram

* increment version

* Update .travis.yml

* remove opencv deps from default setup until we have it on the disc image

* pi setup needed note on updating latest code