SVEA-13: Prevent users from editing addresses from svea

Prevents users from changing address information in addresses that
comes from svea or add a different shipping address in frontend. When
an address is fetched from svea it should not be possible to change
that information or choose a separate shipping address. In backend this
is already dealt with but not in frontend until now.

* If no address could be found all relevant fields are cleared.
* If another payment method is selected the address values will be cleared.
* When switching to svea payment the last address selected, if any, will be selected and the inputs will be populated.

The classes 'svea-hidden' and 'svea-readonly' are used to mark elements
as hidden and/or readonly. This is because magento has no
'payment-method-deselected' event which can be used to remove proper
'readonly' attributes on inputs and hide elements with. Since no such
event is available setting readonly/hiding elements might interfere with
other modules.

Css for the classes 'svea-hidden' and 'svea-readonly' is not included in
this commit.
we should'nt expect that svea is the default method
keep track of non svea address entries and style the inputs
fix bug with stream specific features
Merge pull request #82 from sveawebpay/svea-13

Prevent users from editing addresses from svea