Decide on failure mode when content fails to be read/rendered

[cdata]

In #51 we have a concrete case of trying to access Noosphere content and render it for the user. However, we haven't decided how to deal with cases where the content is expected but not found in the raw source data. Do we render a fallback (perhaps in the spirit of #53 ), or is it a critical failure mode where we should bail completely? Many possible answers here.