Bump package versions for 0.9.2.1.

These should have been bumped in 0.9.2
History item for 0.9.2.1
Banner for 0.9.2.1
update meteor-release-official.json for 0.9.2.1
bump more package numbers for 0.9.2.1
update manifest for 0.9.2.1
update docs
update examples to 0.9.2.1
Merge branch 'release-0.9.2.1'
Merge branch 'master' into devel
temporary solution to springboard in publish-for-arch
also do not springboard from checkout, even in p-f-a
a hidden option to mark packages as unsuccessfully migrated
help message mistype correction
Remove duplicate part from the docs, move JSDoc comment for Npm.require
don't exit on add when only some packages are a noop
Revert default bind IP to 0.0.0.0.

We still use localhost as DDP_DEFAULT_CONNECTION_URL for mobile builds
if another host isn't provided; we just don't want localhost to
overwrite an unspecified host for the proxy to bind to.

Fixes #2596.
MongoHQ has rebranded to Compose
Rename {{> UI.*}} to Template; remove UI uses

Rename inclusion macros (with back-compat) to: Template.dynamic, Template.contentBlock, Template.elseBlock.

Update all uses and mentions of UI in the repo, unless they are there for back-compat or testing reasons.

To do: Run unit tests.  Update docs for UI.dynamic.  Document Template.contentBlock and Template.elseBlock.
Revert default bind IP to 0.0.0.0.

We still use localhost as DDP_DEFAULT_CONNECTION_URL for mobile builds
if another host isn't provided; we just don't want localhost to
overwrite an unspecified host for the proxy to bind to.

Fixes #2596.