Update CHANGELOG from 1.14 upto 1.17

[tesuji]

Fixes #1686.

[tesuji]

r? @kinnison

[kinnison]

This LGTM. @dwijnand ?

@lzutao - Did you create the content using a script, and if so, is it worth adding it, either to the repo or at least as a section in the CONTRIBUTING document?

[dwijnand]

Thanks!

[tesuji]

@kinnison No, I didn't use automatic script to generate CHANGELOG.

I did the following steps to manually update CHANGELOG:

• Make sure your local repository updated and had tags synced with remote:

  git checkout master && git pull --tags

• Write new tag and tag's date in format:

  # [1.16.0] - 2018-12-06

  Date format is ISO-8601. Old tag date could be gotten by: git show -s --format=%ci <tag>.

• Checkout what's changed between old tag and new commit/tag:

  git log --stat --graph 1.16.0...<commit/tag>

  or use GitHub interface: 1.16.0...master

• Filter out commits meet these conditions:

  • Typo fix
  • Small CI fix

• List all other changes in CHANGELOG:

  * [Pull request name/Main content of the change](Link to pull request)

If having time, I could write an automatic script to generate CHANGELOG.