If patient names are stored, the hash function fails on non-ASCII

[Ed McDonagh]

Hash function assumes ASCII, need to add explicit encoding.

When hashing isn't used on store, error appears on search in the interface.

[Ed McDonagh]

Strings are now encoded as UTF-8 before using the hash function. Fixes #400. Have checked that the hash for strings already created will be the same as hashes created after the change.

→ <<cset 07df419b6cb8>>

[Ed McDonagh]

Added update to release notes that I had intended in the last commit! Refs #400

→ <<cset 4e73a9feac56>>