Excel-based sample pages compile on the cloud portal

Code stored in a node is compiled by the portal at runtime, against the libraries that portal ships. The distributed portal did not ship the spreadsheet-import library, although the local development portal did — so sample pages whose code loads data from a workbook compiled fine on a developer's machine and failed in the cloud with an error about a missing MeshWeaver.Import namespace.

The library now ships with the distributed portal too, so those pages compile in both places. This also makes the failure mode less surprising in general: what in-node code can reference is whatever the running portal ships, not whatever exists in the framework.