Check format of release number

Abort with usage if bad.
Fixes #10.
Push HEAD along with tags

Fixes #45.

We switched from `git push` to `git push --tags`, but failed to notice that `update_examples()` committed the changes it made but did not push them.
Pushing the commits and the tags simultaneously seems nice and atomic.
Merge pull request #47 from jrha/check-release-numbering

Check format of release number
Merge pull request #48 from jrha/fix-quattor-version-update

Push HEAD along with tags
Correct tag name for core components

We changed the artifactId in quattor/configuration-modules-core@460640e
but the publishing code was still attempting to use the previous artifactId
this left the repository at the HEAD of master which led to SNAPSHOT versions
being pushed into quattor/template-library-core.
Merge pull request #52 from jrha/fix-core-template-publishing

Correct tag name for core components
get-template-library: update pattern for template-library-core tags
(restrict to tags matching template-library- as other tags are now obsolete)
Merge pull request #56 from jouvin/get-template-library

get-template-library: update pattern for template-library-core tags