Add option to Single Read Sampler to read Text OR Binary

[Peter Doornbosch]

The UI enforces the user to define whether Text or Binary frames will be received. For the Single Read Sampler, this limitation is not really necessary, because the sampler can just read what it receives (as opposed the the Request Response Sampler that needs a type for sending). This will help test scenario’s where servers send both text and binary frames and their order is hard to predict.

To maintain backwards compatibility, the type selection will not be removed, but extended with an option to indicate the user doesn’t care whether Text or Binary is received.