missing dependencies in setup.py

[ndkv]

The following dependencies are requires but missing from setup.py.

• urllib3
• chardet
• certifi
• idna

I'd add them in a pull request but don't know which versions are targeted.

[bartromgens]

@ndkv Those are all dependencies of the requests package and should be collected and installed when using pip install tkapi.

As far as I know I should not list these indirect dependencies in setup.py. Please let me know if this is not correct. And also how and where you got an error, if so?