Deal more gracefully with the case where a image set has been removed but the texts are still there

[brobertson]

Right now, this error is thrown: exerr:ERROR XPTY0004: The actual cardinality for parameter 1 does not match the cardinality declared in the function's signature: app:sortCollection($collectionUri as xs:string) item(). Expected cardinality: exactly one, got 0. [at line 563, column 37, source: /db/apps/lace/modules/app.xql] In function: app:sortCollection(xs:string) [563:17:/db/apps/lace/modules/app.xql] app:sidebyside(node(), map(), xs:string, xs:integer?) [-1:-1:/db/apps/lace/modules/app.xql]

[brobertson]

We need to look more closely at redirecting to an error page and try/catch code blocks.