Added --set-time-path and --get-time-path for issue #10

Pretty simple really. Read the path from a config file, use the current working directory if there is no config. Checks for valid syntax of the flag and valid .json path.

```
--set-time- will fail
--set-time-path=/test/dir/ will fail
--set-time-path=/test/dir/file.js will fail
--set-time-path=/test/dir/file.json will pass
```