Added the ML character type.
Merge branch 'ml' into integration
Merge branch 'integration' into build
Added recommended development tools and a version policy.
Merge branch 'build' into integration

* build:
  Added recommended development tools and a version policy.
Added git options adn git commands to use when developping on Demon.
Merge branch 'build' into integration

* build:
  Added git options adn git commands to use when developping on Demon.
Added some properties on setoids.
Moving Operators to tools.
Merge branch 'math' into integration

* math:
  Moving Operators to tools.
  Added some properties on setoids.