Added html documentation folder to .gitignore.
Added html documentation folder to .gitignore.

thortex/rpi3-webiopi,thortex/rpi3-webiopi,thortex/rpi3-webiopi,thortex/rpi3-webiopi,thortex/rpi3-webiopi,thortex/rpi3-webiopi,thortex/rpi3-webiopi