Move conftest to use testr

Includes the following merges:

• PR #26: Move conftest for tests

Update regression testing post-cxotime

Includes the following merges:

• PR #25: Update regression testing

New test answers post-shiny

Merge pull request #24 from jzuhone/update_answers

Updating answers for shiny

test refactor

refactor tests in response to changes in acis_thermal_check

Use acis_thermal_check 3.0

Includes the following merges:

• PR #20: update psmc_check for acis_thermal_check 3.0

Setting up automated builds

Includes the following merges:

• PR #19: Setting up automated builds

Remove version from setup.py

Merge pull request #18 from jzuhone/version

Remove version from setup.py

February 2020 model recalibration

Merge pull request #17 from jazan12/patch-1

Updated fits for 2019/2020

SCM versioning

Merge pull request #16 from jzuhone/scm

Code changes necessary for SCM versioning

July 2018 PSMC model recalibration

Merge pull request #15 from acisops/psmc_2018_update

Psmc 2018 update