Command line render script does not set indexer

[hholzgra]

The command line script does not know about the indexer additions, and so fails to render when a layout with an index is requested

[hholzgra]

• [x] make it set "Street" indexer as default choice
• [x] add command line option to choose a different indexer
• [x] add --list-indexers option
• [x] validate chosen indexer as part of option processing