Proposed changes to ng_to_nasa

[teubert]

A few proposed changes:

1. For backwards compatibility, remove the atleast_1d- now a scalar returns a scalar and an array returns an array <- @MikeAndSpencer what do you think of this? Will it cause any problems
2. Fix issue with thresholds_met equation
3. Add an example
4. Add tests
5. Add a note to the template about using np functions over math
6. Make thrown_object, circuit, and pneumatic_valve models compatible
7. Update check to use np.isscalar

[lgtm-com]

This pull request introduces 1 alert when merging d8b680a into 38ff274 - view on LGTM.com

new alerts:

• 1 for Variable defined multiple times

[lgtm-com]

This pull request introduces 1 alert when merging 571d9c6 into 38ff274 - view on LGTM.com

new alerts:

• 1 for Variable defined multiple times

[lgtm-com]

This pull request introduces 1 alert when merging 10f9308 into 38ff274 - view on LGTM.com

new alerts:

• 1 for Variable defined multiple times

[MikeAndSpencer]

A few proposed changes:

1. For backwards compatibility, remove the atleast_1d- now a scalar returns a scalar and an array returns an array <- @MikeAndSpencer what do you think of this? Will it cause any problems
2. Fix issue with thresholds_met equation
3. Add an example
4. Add tests
5. Add a note to the template about using np functions over math
6. Make thrown_object, circuit, and pneumatic_valve models compatible
7. Update check to use np.isscalar

@teubert I am good with getting rid of atleast_1d. It was something that Cason put in because of mismatched datatypes that he ran into when we were working on MCMC but it didn't affect the vectorization.