Created options for using a full non-interactive mode

I've created the following options:
* -l, --list: print a list with the courses and their respective numbers;
* -c, --course-number: specify the course number to skip this step in the interactive process (user must already know the desired course number, which can be done using the previous option);
* -w, --week: specify the week number to skip this step in the interactive process, and make the whole process non-interactive (user must already know the desired week number, which can be done using the next option);
* -lw, --list-weeks: print a list of the weeks of a course specified with the -c option.

I've also corrected an IndexError that was occurring in my system. In order to do that, I've done a substitution as shown below:
```
-        subsUrls += [BASE_URL + regexpSubs.search(container).group(2) + "?videoId=" + id + "&language=en"
+        subsUrls += [BASE_URL + regexpSubs.search(container).group(1) + "?videoId=" + id + "&language=en"
```