#61 (Dec 18, 2017, 9:57:58 AM)

1. fix tail flex model to use theta from bending model (commit: f08b57d) (details / githubweb)
2. have tailboom inhereit from spar model (commit: dc69f8f) (details / githubweb)
3. use single model for tail boom bending, call beam model in bending (commit: fef0178) (details / githubweb)
4. allow for dynamic inheritance of tailboom model; constrain moment in tb (commit: 6c60169) (details / githubweb)

GitHub pull request #146 of commit 6c60169cfdac94539646c9cf6600c833869f63e3, no merge conflicts.