Enhancement - #307 show command

- introduced new show command to display configuration settings
- config command is used to just set config values
- modified documentation
- modified some unit tests calling 'task config' to 'task show'

src/main.h

@@ -71,6 +71,7 @@ int handleCompletionConfig (std::string &);
 int handleCompletionVersion (std::string &);
 int handleVersion (std::string &);
 int handleConfig (std::string &);
+int handleShow (std::string &);
 int handleDelete (std::string &);
 int handleStart (std::string &);
 int handleStop (std::string &);