Added Python mode to the list.
Merge branch 'master' of https://github.com/processing/processing-web

# By David Wicks (5) and others
# Via David Wicks (1) and others
* 'master' of https://github.com/processing/processing-web:
  Thank You added to Overview
  Several refinements to mouse-related reference descriptions
  updates for 2.1.2
  Clarified mouseX and mouseY behavior
  Minor rephrasing and typo fixes on rotate() description
  swapped 2 filenames
  #380 typo
  Handling links to PGraphics, etc correctly again.
  Changes to @see tag evaluation.
  Added a small java file for testing reference builder.
  More People updates
  Mod to People page
  Added information about JAVA_HOME to README.md
  Build script working again.