SimpleWorkflow service binding specific error handling - EUCA-10021

The SimpleWorkflow service now responds with JSON format error messages
when exceptions occur. The special SOAP error response formatting is
moved from NioServerHandler to SoapMarshallingHandler. Bindings with
a specific format for errors can now implement the
ExceptionMarshallerHandler interface.

EUCA-10021
EC2 VPC resource condition key TypeMapper fix - EUCA-10015

The VPC IAM policy condition key @TypeMapper now transforms from the
correct (Vpc) type.

EUCA-10015
Merge remote-tracking branch 'origin/dev/sjones/EUCA-10015' into testing
Merge remote-tracking branch 'origin/dev/sjones/EUCA-10021' into testing
Fix HMAC signature test - EUCA-10021