Uses commit message from GitHub by redirecting the GitHub merge form.

This also required modifying the content security policy to whitelist our server.

Closes #2

Squash commit created by Whaler.
Closes and deletes PRs during merges, and links between comments and PRs.

Closes #11

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Squash commit from https://github.com/ndahlquist/Whaler/pull/12 created by Whaler.
Make the modification to GitHub faster by not waiting for window.onload.

Closes #9 

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Squash commit from https://github.com/ndahlquist/Whaler/pull/14 created by Whaler.
Added PyGithub as a Git submodule. Closes #3.

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Squash commit from https://github.com/ndahlquist/Whaler/pull/16 created by Whaler.
Fixed old ref after backwards merge. Closes #17.