added generic fastener element

[obucklin]

closes #319

This adds a generic fastener element which sets the stage for carious connectors like brackets and steel plates. We may want to add another generic 'dowel' class or we could include screws, nails, dowels, etc here under fastener. Heirarchy TBD.

What type of change is this?

• Bug fix in a backwards-compatible manner.
• New feature in a backwards-compatible manner.
• Breaking change: bug fix or new feature that involve incompatible API changes.
• Other (e.g. doc update, configuration, etc)

Checklist

Put an x in the boxes that apply. You can also fill these out after creating the PR. If you're unsure about any of them, don't hesitate to ask. We're here to help! This is simply a reminder of what we are going to look for before merging your code.

• I added a line to the CHANGELOG.md file in the Unreleased section under the most fitting heading (e.g. Added, Changed, Removed).
• I ran all tests on my computer and it's all green (i.e. invoke test).
• I ran lint on my computer and there are no errors (i.e. invoke lint).
• I added new functions/classes and made them available on a second-level import, e.g. compas_timber.datastructures.Beam.
• I have added tests that prove my fix is effective or that my feature works.
• I have added necessary documentation (if appropriate)

[obucklin]

i'm not sure what

"I added new functions/classes and made them available on a second-level import, e.g. compas_timber.datastructures.Beam"

means, so I clicked it

[obucklin]

Now with 100,000,000,000,000,000,000% more unit tests!

[papachap]

Now with 100,000,000,000,000,000,000% more unit tests!

haha I see that Chen's presentation yesterday really had an impact on you!

[chenkasirer]

I am still confused about Fastener it looks like a partial copy of Element and Beam but not clear how it's used. From our whiteboard session I'm missing the FastenerJoint part and how it interacts with FastenerElement. Should we have another session to discuss?

[obucklin]

ready for re-review

[obucklin]

I am still confused about Fastener it looks like a partial copy of Element and Beam but not clear how it's used. From our whiteboard session I'm missing the FastenerJoint part and how it interacts with FastenerElement. Should we have another session to discuss?

I don't see the need for a separate FastenerJoint ATM. do you?

[chenkasirer]

I am still confused about Fastener it looks like a partial copy of Element and Beam but not clear how it's used. From our whiteboard session I'm missing the FastenerJoint part and how it interacts with FastenerElement. Should we have another session to discuss?

I don't see the need for a separate FastenerJoint ATM. do you?

ah I think what's happening is that you're doing all that in that other PR (BallFastenerJoiningBallWithTentaclesJoint). so maybe that's why I'm confused.

[obucklin]

I am still confused about Fastener it looks like a partial copy of Element and Beam but not clear how it's used. From our whiteboard session I'm missing the FastenerJoint part and how it interacts with FastenerElement. Should we have another session to discuss?

I don't see the need for a separate FastenerJoint ATM. do you?

ah I think what's happening is that you're doing all that in that other PR (BallFastenerJoiningBallWithTentaclesJoint). so maybe that's why I'm confused.

tryna keep it grainular

[chenkasirer]

LGTM