amber.js tries to find itself also by id not just as last <script>
amber.js tries to find itself also by id not just as last <script>

When loaded all scripts asynchronously, the
'last <script> tag' trick is unable to find the right one,
so amber.js does not see its path and possible data-libs.

In case of async loading, giving the <script> well-known id
'amber-path-mapper' allows it to find itself.

amber-smalltalk/amber,amber-smalltalk/amber,adrian-castravete/amber,amber-smalltalk/amber,adrian-castravete/amber,adrian-castravete/amber