add store payment method to spreedly service.
Add payment verification method, removed some _'s
add more transaction process methods, add additional transaction properties.
Merge branch 'master' of https://github.com/hross/Spreedly.Net

Conflicts:
	src/Spreedly.Net/Model/AsyncClient.cs
	src/Spreedly.Net/Model/IAsyncClient.cs
	src/Spreedly.Net/Service/SpreedlyService.cs
update transaction parsing xml, add created date
Add support for a single transaction query.
add a way to save/retrieve raw transaction XML
add since token and order to transaction query
Merge pull request #2 from hross/master

Add store payment method et. al. to Spreedly service