Add an explicit distinction between a command's description and summary.

Add an explicit distinction between a command's description and summary.

ff4dd9a8e2255f998fd2f017205d9f908f82b8de broke some users who were
relying on only the first line of a command's description being included
in its runner's usage as a summary. That is once again the default
behavior.

To support the use case described in #42, there's a new Command.summary
getter that explicitly controls the summary included in the parent
runner's usage. This defaults to the first line of the description, but
may be overridden to declare a multi-line summary.

Closes #42

R=rnystrom@google.com

Committed: https://github.com/dart-lang/args/commit/0160fae46e40562acafd15c793d59a38575568a8

[Bob Nystrom, 2016-03-17 22:47:19]

lgtm

[nweiz, 2016-03-17 22:53:08]

Description was changed from

==========
Add an explicit distinction between a command's description and summary.

ff4dd9a8e2255f998fd2f017205d9f908f82b8de broke some users who were
relying on only the first line of a command's description being included
in its runner's usage as a summary. That is once again the default
behavior.

To support the use case described in #42, there's a new Command.summary
getter that explicitly controls the summary included in the parent
runner's usage. This defaults to the first line of the description, but
may be overridden to declare a multi-line summary.

Closes #42

R=rnystrom@google.com
==========

to

==========
Add an explicit distinction between a command's description and summary.

ff4dd9a8e2255f998fd2f017205d9f908f82b8de broke some users who were
relying on only the first line of a command's description being included
in its runner's usage as a summary. That is once again the default
behavior.

To support the use case described in #42, there's a new Command.summary
getter that explicitly controls the summary included in the parent
runner's usage. This defaults to the first line of the description, but
may be overridden to declare a multi-line summary.

Closes #42

R=rnystrom@google.com

Committed:
https://github.com/dart-lang/args/commit/0160fae46e40562acafd15c793d59a385755...
==========

[nweiz, 2016-03-17 22:53:10]

Committed patchset #1 (id:1) manually as
0160fae46e40562acafd15c793d59a38575568a8 (presubmit successful).