Create BicCandidate class to encapsulate related logic

As we add new services, BIC candidate related logic needs to be extracted into a single class. It adds some more logic and should handle all types of input.
Add IBAN validator response class

Use this class to handle the SOAP response object and convert its data in a typical ruby structure.
Add method to validate IBANs
Add abstract bank class to encapsulate bank related data
Push version 0.0.2
Merge pull request #1 from railslove/iban-validation

Support validate_iban endpoint