Property objects

[spoehner]

Properties are now handled as objects

• There is a factory that does the conversion from the old array format to an object.
• Compilation is moved to the properties themselves - if possible.
  Unfortunately the compiler is too much intertwined with everything, so not all properties can do that yet.
• Added proper type hints to alle methods handling properties.
• To help the transition, I kept ArrayAccess for Property, but it throws an Exception.

[coveralls]

Coverage decreased (-0.3%) to 91.996% when pulling a493d6a on spoehner:property-object into 5d7e298 on MarcusSchwarz:master.

[MarcusSchwarz]

Thank you, @spoehner, merged!