- validation of  ski-, boardprofile, profile and profile proxy
- introduced two new validator classes for this purpose
- profile is valid if in ski- and boardprofile all attrs are set
OR in skiprofile all attr are set and in boardprofile none
OR vice versa
- profile is invalid if in ski- and boardprofile all attr are nil
OR if in ski- or boardprofile only some attr are set (independent of validness of other profile)
- introduced board profile attr in view
- ref #42