[polymer & pkgs] update pubspecs to prepare for -pre.0 release

[polymer] update pubspecs to prepare for -pre.0 release

R=sigmund@google.com

Committed: https://code.google.com/p/dart/source/detail?r=33178

[Jennifer Messerly, 2014-02-28 21:52:54]

I've attempted to standardize on:

* sdk >= 1.2
* args & unittest & analyzer matching latest version
* cleanup around custom_element and mutation_observer


Not sure how to test this before upload... ideas?

[Siggi Cherem (dart-lang), 2014-02-28 22:02:08]

lgtm! thanks for preparing this!

For testing, I don't have simple ideas. The one thing I'm thinking of is that
pub used to have the notion of a dev-server that you can use for
publishing/installing from, but I don't know how you could start one or how to
configure pub to use it.

Eventually it might be nice to ask pub to expose its constraint solver as a
package, so one could test out scenarios with multiple pubspecs...

[Siggi Cherem (dart-lang), 2014-02-28 22:03:38]

note that as soon as you start releasing packages, our bots will pick those up
(on the next change) and you can run those tests locally using the
--use_public_packages flag on pkgbuild tests

[Jennifer Messerly, 2014-02-28 22:59:29]

Committed patchset #6 manually as r33178 (presubmit successful).

[Jennifer Messerly, 2014-02-28 23:33:19]

fwiw, I ended up testing it by fake populating my pub cache and `pub upgrade
--offline`. It caught a few issues such as invalid YAML in mutation_observer
pubspec.