Bmi unit test - Githubissues

Include BMI unit testing for PET

unit test C script main_unit_test_bmi.c
make and run shell make_and_run_bmi_unit_test.sh - uses method 1 config but others are commented out
configurations & forcings
README gives instructions on how to run
All bmi functions pass
Updated get_end_time() def - required float.h to be included in pet.h.
- Tested all build/run to confirm this change wouldn't have other impacts

Checklist

[ ] PR has an informative and human-readable title
[ ] Changes are limited to a single goal (no scope creep)
[ ] Code can be automatically merged (no conflicts)
[ ] Code follows project standards (link if applicable)
[ ] Passes all existing automated tests
[ ] Any change in functionality is tested
[ ] New functions are documented (with a description, list of inputs, and expected output)
[ ] Placeholder code is flagged / future todos are captured in comments
[ ] Visually tested in supported browsers and devices (see checklist below :point_down:)
[ ] Project documentation has been updated (including the "Unreleased" section of the CHANGELOG)
[ ] Reviewers requested with the Reviewers tool :arrow_right: