configure.ac: require nuspell >= 4.1.0 (fixes #267)
configure.ac: require nuspell >= 4.1.0 (fixes #267)

AbiWord/enchant,rrthomas/enchant,AbiWord/enchant,AbiWord/enchant,rrthomas/enchant,rrthomas/enchant,AbiWord/enchant,rrthomas/enchant