Add error message for setup.py

[Yelinz]

pip removed pip.main() in the version 10.0, therefore you need to manually install the required packages.

If you run python setup.py it would result in:

Traceback (most recent call last):
  File "setup.py", line 18, in <module>
    pip.main(['install', package])
AttributeError: 'module' object has no attribute 'main'

[Qh0stM4N]

Setup needs to be rewritten. This can be regarded as an obvious solution.