Add sphinx-copybutton to allow copying code blocks with a single clic…

[stevepiercy]

…k of a button

Closes #682.

[coveralls]

Pull Request Test Coverage Report for Build 9772008518

Warning: This coverage report may be inaccurate.

This pull request's base commit is no longer the HEAD commit of its target branch. This means it includes changes from outside the original pull request, including, potentially, unrelated coverage changes.

• For more information on this, see Tracking coverage changes with pull request builds.
• To avoid this issue with future PRs, see these Recommended CI Configurations.
• For a quick fix, rebase this PR at GitHub. Your next report should be accurate.

Details

• 0 of 0 changed or added relevant lines in 0 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 97.559%

---

Totals
Change from base Build 9767068472:	0.0%
Covered Lines:	3078
Relevant Lines:	3155

---

💛 - Coveralls

[coveralls]

Pull Request Test Coverage Report for Build 9772277927

Details

• 0 of 0 changed or added relevant lines in 0 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 97.559%

---

Totals
Change from base Build 9772012706:	0.0%
Covered Lines:	3078
Relevant Lines:	3155

---

💛 - Coveralls

[coveralls]

Pull Request Test Coverage Report for Build 9778016271

Warning: This coverage report may be inaccurate.

This pull request's base commit is no longer the HEAD commit of its target branch. This means it includes changes from outside the original pull request, including, potentially, unrelated coverage changes.

• For more information on this, see Tracking coverage changes with pull request builds.
• To avoid this issue with future PRs, see these Recommended CI Configurations.
• For a quick fix, rebase this PR at GitHub. Your next report should be accurate.

Details

• 0 of 0 changed or added relevant lines in 0 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 97.559%

---

Totals
Change from base Build 9777998693:	0.0%
Covered Lines:	3078
Relevant Lines:	3155

---

💛 - Coveralls