RFC: Handle `j -- -foo` (for bash and zsh only)

Ref: #310 

It only fixes the functions for Bash and Zsh for now.

Is it OK like this?
I've only tested the zsh version but it doesn't work for me:

```
╭─wting@mission ~ ‹python-2.7.7›
╰─➤  j -gdrive                                                                               2014.09.06 10:52:00 PDT
usage: autojump [-h] [-a DIRECTORY] [-i [WEIGHT]] [-d [WEIGHT]] [--complete]
                [--purge] [-s] [-v]
                [DIRECTORY [DIRECTORY ...]]
autojump: error: unrecognized arguments: -gdrive
╭─wting@mission ~ ‹python-2.7.7›
╰─➤  j -- -gdrive                                                                        2 ↵ 2014.09.06 10:52:02 PDT
usage: autojump [-h] [-a DIRECTORY] [-i [WEIGHT]] [-d [WEIGHT]] [--complete]
                [--purge] [-s] [-v]
                [DIRECTORY [DIRECTORY ...]]
autojump: error: unrecognized arguments: -gdrive
autojump: directory '-gdrive' not found
Try `autojump --help` for more information.
╭─wting@mission ~ ‹python-2.7.7›
╰─➤  j gdrive                                                                            1 ↵ 2014.09.06 10:52:04 PDT
/Users/wting/riyoda-gdrive
╭─wting@mission ~/riyoda-gdrive ‹python-2.7.7›
╰─➤                                                                                          2014.09.06 10:52:25 PDT
```

`autojump -gdrive` is still being interpreted as an option at the python level.