"ten-minute-rule" installation

Setup with conda

• @mohanty readme
• @christian_eichenberger review readme
• @christian_eichenberger remove pycairo from setup.py
• @christian_eichenberger use setup in tox to verify the approach
• @hagrid67 tests getting_started/getting_started.bat on Windows
• @christian_eichenberger tests getting_started/getting_started.sh on os x
• @mohanty user tests getting_started/getting_started.bat/sh
  • debian
  • ubuntu
  • os x
  • windows
• @mohanty document incompatibility Windows for py37 (will be fixed in #100 )