Refactor IPAddr v4 initialization from string. (fixes #775)

Revived code from old dotted_to_addr function to parse the
dotted address string directly instead of canonicalizing and
passing to inet_pton.

src/IPAddr.h

@@ -261,14 +261,6 @@ public:
 
 	unsigned int MemoryAllocation() const { return padded_sizeof(*this); }
 
-	/**
-	 * Returns a canonicalized IPv4 dotted-decimal string such that
-	 * leading zeroes of each decimal part are removed.
-	 *
-	 * @param s String containing an IPv4 address in dotted-decimal notation.
-	 */
-	static std::string CanonIPv4(const std::string& s);
-
 private:
 	/**
 	 * Initializes an address instance from a string representation.