fix bigmlAuth should consistently have trailing ; char

[eschultink]

if you pass in projectId/organization when construction instances of AbstractResource, its internal variable bigmlAuth will not end up with a trailing ; - but if you don't pass them, it will.

This inconsistency can cause unexpected behavior if you pass an explicit query string to various request methods on AbstractResource later, as that queryString will need to begin with ; or not depending on how the resource was initially constructed.

[javinp]

@eschultink Thank you for your collaboration, we have deployed a new version including this fix in Maven Central Repository