Changed values of log levels

When verbose level was set, log messages with verbose level were not displaying. The reason was that the condition for allowed logging level (https://github.com/talyssonoc/WolverineJS/blob/master/lib/wolverine.js#L76) was false with `wolverineObj.level` set to `0`.

I changed values of log levels to be equal: 10, 20, 30.. This is the common used practice for logging libraries, especially for the case, when you want to add a custom log level with the weight between the existing ones.

I have written the falling test for this issue and this changes makes this test pass.