Modify customer address validation to allow no address on Windows flavor

At first I just removed the validation, but I think something should be there - since sending an empty address does fail.

You are able to send nothing at all, customer.addresses = nil seems to work;

		<Add xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema" RequestId="95bd8691b4b6d8a8e20d4a1eea28349c" xmlns="http://www.intuit.com/sb/cdm/v2">
			<ExternalRealmId>762087535</ExternalRealmId>
			<Object xsi:type="Customer"> 
				<TypeOf>Person</TypeOf> 
				<Name>Steve Klabnick</Name> 
				<Phone> 
					<DeviceType>LandLine</DeviceType> 
					<FreeFormNumber>6678881212</FreeFormNumber> 
					<Default>true</Default> 
					<Tag>Business</Tag> 
				</Phone> 
				<Email> 
					<Address>troy+steve@testing.com</Address> 
					<Default>true</Default> 
					<Tag>Business</Tag> 
				</Email> 
				<DBAName /> 
			</Object>
		</Add>

		<RestResponse xmlns="http://www.intuit.com/sb/cdm/v2">
			<Success RequestId="95bd8691b4b6d8a8e20d4a1eea28349c">
				<PartyRoleRef>
					<Id idDomain="NG">929334</Id>
					<SyncToken>1</SyncToken>
					<LastUpdatedTime>2013-08-26T04:14:30Z</LastUpdatedTime>
					<PartyReferenceId idDomain="NG">1008617</PartyReferenceId>
				</PartyRoleRef>
				<RequestName>CustomerAdd</RequestName>
				<ProcessedTime>2013-08-26T04:14:30Z</ProcessedTime>
			</Success>
		</RestResponse>

I have no idea how to communicate this in a short validation error :)