Michał Kowal

- Change FailedSpecification object to Specification Info and use for all validation results - Add IsNegation flag to validation result

- treat exceptions like validation error - provide new Exception based on Validation result - allow to throw validation exception

- Run task for multiple databases - MsSql, LiteDB, PostreSQL - Pass connection string and other parameters from AppVeyor

[WIP] Add GreedyMockAttribute

3

Closes #766 I prepared also abstract MockCustomizeAttribute for any further attributes (like for xUnit, NUnit etc)