Search: Accented characters, ampersands, negative numbers and other special characters

[kcondon]

This was suggested by Eleni during discussions around search issues with accented characters.

The suggestion is to allow searching both using the original accented characters and without, in those cases where a user may not have access to accented keyboard, etc.

[pdurbin]

See also #818 (comment) and the search internationalization ticket at #326.