Support Base Templates and Blocks in partial rendering

Support Base Templates and Blocks in partial rendering (or have another function/command that does support it)

In the example
{{ $page := partial "map.html" $ctx }}

map.html apparently cannot use a base template so must repeat the content of baseof.html to give the same look/feel to the page. For context see: How to create multiple views of same content? - #11 by jmooring