Date Normaliser

Examples:

• 1963-67 (http://feeds.boxuk.com/convert/date/1963-67)
• 1840s (http://feeds.boxuk.com/convert/date/1840s)
• 200 BC - 1200 AD (http://feeds.boxuk.com/convert/date/200+BC+-+1200+AD)
• 7th Century BC (http://feeds.boxuk.com/convert/date/7th+Century+BC)
• Early 17th century (http://feeds.boxuk.com/convert/date/Early+17th+century)