code: protected String generateSignature(String secret, Map<String, String> map) {
          return sha256Hex(buildSignatureString(secret, map));
      }
docs: Generates a signature with the algorithm specified by episodic:
  <p/>
  API Signature Generation
  <ol>
  <li> All API requests must include a signature parameter. The signature is generated performing the following steps.
  <li> Concatenate all query parameters except the API Key in the format "name=value" in alphabetical order by parameter name. There should not be an ampersand or any separator between "name=value" pairs.
  <li> Append the string from step 1 to the Secret Key so that you have [Secret Key][String from step 1] (ex. 77c062e551279b0a0b8bc69f9709f33bexpires=1229046347show_id=13).
  <li>Generate the SHA-256 hash value for the string resulting from steps 1 and 2.
  <ol>
  
  @param secret The secret key provided by episodic.
  @param map    A map of the parameters to be sent to.
  @return The signature needed for an episodic request.