Extend Util.noaccents to work for non-french characters

The Util.noaccents function is intended to replace accented characters used in different languages with an ASCII-7 equivalent, like â => a, ? => t. The version up to Beta1 did this only for characters found in the french alphabet, and using a hardcoded latin-1 string.

The new version does this for most translatable unicode characters, and using the \uNNNN notation.