Update Tutorial 1: The Basics

Tasks to be completed for [Tutorial 1](https://github.com/firelab/windninja/blob/master/doc/tutorials/WindNinja_tutorial1.pdf):

- [ ] Review tutorial descriptions for accuracy, update as needed
- [ ] Update navigation tree pictures to match new GUI look
- [ ] Add section for 

Latex file and tutorial images found [here](https://github.com/firelab/windninja/tree/master/doc/tutorials/tutorial_1).