Should be able to specify if it's OR or AND condition

[dstj]

Digging into the code to understand my issue with #9, I noticed that the IfQueryArg() condition is forced as an "OR" condition:

Stubbery/src/Stubbery/RequestMatching/Setup.cs

Line 23 in cc58462

orConditions = new Dictionary<ConditionGroup, List<IPrecondition>>

I believe there should be an extra optional parameter to (maybe) all conditions to specify if we want it to be an AND or an OR. So

Stubbery/src/Stubbery/RequestMatching/Setup.cs

Line 87 in cc58462

public ISetup IfQueryArg(string argName, string argValue)

would be

public enum ConditionType { Or, And }

public ISetup IfQueryArg(string argName, string argValue, ConditionType conditionType = ConditionType.Or)

This would increase flexibility.