Rename Inference-Engine to Fiats

[rouson]

This pull request accomplishes a long-envisioned renaming of Inference-Engine.

Background

There prior name "Inference-Engine" has several problems, including

1. Although this repository originally focused on inference, it now also supports training neural networks and devotes more code to supporting and demonstrating training than to inference.
2. The term "inference engine" has a meaning that predates deep learning and is only peripherally related to neural networks in the sense that both are methods for generating predictions or making decisions.

Rationale

Intended expansions of Fiats as an acronym:

1. “Functional inference and training for surrogates” or
2. “Fortran inference and training for science”

The literal meaning of "Fiats":

The macOS built-in dictionary's definition is

fiat | ˈfēət, ˈfēˌät |
noun
a formal authorization or proposition; a decree: adopting a legislative review program, rather than trying to regulate by fiat.
• an arbitrary order: the appraisal dropped the value from $75,000 to $15,000, rendering it worthless by bureaucratic fiat.

ORIGIN
late Middle English: from Latin, ‘let it be done’, from fieri ‘be done or made’.

This definition fits in the sense that neural networks are mathematically formal methods for producing propositions based on prior training. The additional connotation of “an arbitrary order” is either less of a good fit or could be a good reminder of the need for caution when accepting answers produced by AI.

Provenance

This software originated at Berkeley Lab, a U.S. Department of Energy national laboratory managed by the University of California (UC). Thus, "Fiats" is also a nod to the UC motto "Fiat lux," which translates from Latin as "Let there be light."

Uniqueness

Searches of GitHub, BitBucket, and GitLab find several repositories with names containing "fiat" but none named "fiats".