Update changelog with patch release notes

Kevin/Bill, there was a good suggestion in #25374 that we should maintain the changelog even for SDK patch releases. I think that is a good idea. I went back and added entries for 1.13.1 and 1.13.2. What do you think?

Fixes #25374

R=kevmoo@google.com

Committed: https://github.com/dart-lang/sdk/commit/1bf4ee0841927f448468ba1216f929b28af31347

[mit, 2016-01-11 15:51:10]

Description was changed from

==========
Kevin/Bill, there was a good suggestion in #25374 that we should maintain the
changelog even for SDK patch releases. I think that is a good idea. I went back
and added entries for 1.13.1 and 1.13.2. What do you think?

Fixes #25374
==========

to

==========
Kevin/Bill, there was a good suggestion in #25374 that we should maintain the
changelog even for SDK patch releases. I think that is a good idea. I went back
and added entries for 1.13.1 and 1.13.2. What do you think?

Fixes #25374
==========

[mit, 2016-01-11 15:51:11]

mit@google.com changed reviewers:
+ kevmoo@google.com, whesse@google.com

[mit, 2016-01-11 15:51:12]

mit@google.com changed reviewers:
- kevmoo@google.com, whesse@google.com

[mit, 2016-01-11 15:59:20]

mit@google.com changed reviewers:
+ kevmoo@google.com, whesse@google.com

[Bill Hesse, 2016-01-11 17:55:13]

https://codereview.chromium.org/1573163002/diff/1/CHANGELOG.md
File CHANGELOG.md (right):

https://codereview.chromium.org/1573163002/diff/1/CHANGELOG.md#newcode80
CHANGELOG.md:80: * Pub get crash on ARM: Fixes a crash triggered when running
'pub get' on ARM processors such as those on a Raspberry Pi (SDK issue
[24855](https://github.com/dart-lang/sdk/issues/24855))
Long lines, beyond those required by the links.

[kevmoo, 2016-01-11 18:03:01]

LGTM – pending long line fix.

Thanks!

[mit, 2016-01-12 10:09:24]

Description was changed from

==========
Kevin/Bill, there was a good suggestion in #25374 that we should maintain the
changelog even for SDK patch releases. I think that is a good idea. I went back
and added entries for 1.13.1 and 1.13.2. What do you think?

Fixes #25374
==========

to

==========
Kevin/Bill, there was a good suggestion in #25374 that we should maintain the
changelog even for SDK patch releases. I think that is a good idea. I went back
and added entries for 1.13.1 and 1.13.2. What do you think?

Fixes #25374

R=kevmoo@google.com

Committed:
https://github.com/dart-lang/sdk/commit/1bf4ee0841927f448468ba1216f929b28af31347
==========

[mit, 2016-01-12 10:09:25]

Committed patchset #3 (id:40001) manually as
1bf4ee0841927f448468ba1216f929b28af31347 (presubmit successful).