Black screen in Spyder3 IDE on GNU/Linux

If Spyder3 shows only black screen after launching that may be a "nvidia + pyqt5" bug. .
Solution is pretty simple.

1. Install pyopengl package. Use yours distro's package manager or pip
   pip install PyOpenGL PyOpenGL_accelerate
2. Add
   from OpenGL import GL
   into site-packages/spyder/app/start.py file.
   If spyder installed locally for user look path like ~/.local/lib/python3.5/site-packages/spyder/app/start.py
   Else look path like /usr/lib/python3.5/site-packages/spyder/app/start.py

Similar actions may fix bug for other applications developed with PyQt5 too.
Bug description on GitHub.