Update changelog for 1.7.0 release

[natecook1000]

No description provided.

[rgoldberg]

@natecook1000 @rauhul Is there any way to merge #808 & #837 for 1.7.0?

#808 passed all the tests months ago, I updated the code to handle the 2 small comments back then, and it would be useful to release.

#837 was submitted last week, but it is simple. It only affects a few lines of code.

I'm available to answer any questions, make any changes you request, etc.

Thanks for any consideration.