Bundle instapy-chromedriver as a dependency

Currently you need to explicitly add it to PATH if not already done. This was the error for me.
Ideally it should work out of the box like [InstaPy](https://github.com/timgrossmann/InstaPy).

> Traceback (most recent call last):
> File "classify_profiles.py", line 21, in
> browser = webdriver.Chrome('./assets/chromedriver', chrome_options=chrome_options)
> File "/Users/ishandutta2007/.pyenv/versions/3.6.0/lib/python3.6/site-packages/selenium/webdriver/chrome/webdriver.py", line 73, in __init__
> self.service.start()
> File "/Users/ishandutta2007/.pyenv/versions/3.6.0/lib/python3.6/site-packages/selenium/webdriver/common/service.py", line 83, in start
> os.path.basename(self.path), self.start_error_message)
> selenium.common.exceptions.WebDriverException: Message: 'chromedriver' executable needs to be in PATH. Please see https://sites.google.com/a/chromium.org/chromedriver/home
>
>