changed gulp validate-xml behaviour for mail add-ins to use the correct object traversal to read the SourceLocation DefaultValue
changed gulp validate-xml behaviour for mail add-ins to use the correct object traversal to read the SourceLocation DefaultValue

WrathOfZombies/generator-office,jasonjoh/generator-office,WrathOfZombies/generator-office,jasonjoh/generator-office,jasonjoh/generator-office,WrathOfZombies/generator-office,OfficeDev/generator-office