Adds service objects for processing sales and slims down Account

Squashed commit of the following:

commit 13517942f5e9990e5879a1e4a29a65bb7b6d2400
Author: Owen Bannister <owen@bandadbro.com>
Date:   Thu Oct 9 08:55:59 2014 +0100

    delete redundant lines from Account

commit 35e4c0c4af884bb2b6bf20c6671e4e1595d19188
Author: Owen Bannister <owen@bandadbro.com>
Date:   Wed Oct 8 17:20:32 2014 +0100

    fix account email change on confirmation

commit ba0c70e43e90d9e89708fe698f7f80f5c2dc9cb4
Author: Owen Bannister <owen@bandadbro.com>
Date:   Wed Oct 8 14:01:03 2014 +0100

    refactor policies to inherit from Scope

commit 8e901a752436ca8a63c93df2d43b985a159046ed
Author: Owen Bannister <owen@bandadbro.com>
Date:   Thu Sep 25 11:44:41 2014 +0100

    fix cucumber for change to vat_allowed

commit 5c2fc90fac5ecc16414b1c79e8869cf2c8574290
Author: Owen Bannister <owen@bandadbro.com>
Date:   Thu Sep 25 11:25:14 2014 +0100

    adds change_stripe_email and changes account controller to use services for update

commit 7cdffd062fdc07d7be651f005687f72f44e2f140
Author: Owen Bannister <owen@bandadbro.com>
Date:   Wed Sep 24 22:17:25 2014 +0100

    adds cancel sale and spec

commit 80c6f218488fc95bebf07a203ed7adfc21949485
Author: Owen Bannister <owen@bandadbro.com>
Date:   Wed Sep 24 21:49:36 2014 +0100

    fix vat_enabled vs vat_allowed

commit 046c96ee5ed107849eb79306808d1600232226f3
Author: Owen Bannister <owen@bandadbro.com>
Date:   Wed Sep 24 17:04:54 2014 +0100

    process sale spec and migration

commit b7fb729d3d6372b1eea38a60b739748c447e9de9
Author: Owen Bannister <owen@bandadbro.com>
Date:   Wed Sep 24 17:03:37 2014 +0100

    wip on sales process service object