Fix #67, Moves interface definition files to inc

[chillfig]

Checklist (Please check before submitting)

• [x] I reviewed the Contributing Guide.
• [x] I signed and emailed the appropriate Contributor License Agreement to GSFC-SoftwareRelease@mail.nasa.gov and copied cfs-program@lists.nasa.gov.

Describe the contribution

• Fixes #67

Testing performed make install lcov

Expected behavior changes No expected behavior change.

System(s) tested on -Ubuntu 18.04

Additional context N/A

Third party code If included, identify any third party code and provide text file of license

Contributor Info - All information REQUIRED for consideration of pull request -Justin Figueroa, Vantage

[chillfig]

closer look at Build Doc workflow needed