Interface changes since 1.0

[Benjamin Kehlet]

This bug report is for collecting not backward compatible API changes since version 1.0. Fixing this bug = documenting the interface changes clearly in the release notes (web page).

* Rename of mesh classes
    dolfin/generation/Box.h => dolfin/generation/BoxMesh.h
    dolfin/generation/Interval.h => dolfin/generation/IntervalMesh.h
    dolfin/generation/Rectangle.h => dolfin/generation/RectangleMesh.h
    dolfin/generation/UnitCircle.h => dolfin/generation/UnitCircleMesh.h
    dolfin/generation/UnitCube.h => dolfin/generation/UnitCubeMesh.h
    dolfin/generation/UnitInterval.h => dolfin/generation/UnitIntervalMesh.h
    dolfin/generation/UnitSphere.h => dolfin/generation/UnitSphereMesh.h
    dolfin/generation/UnitSquare.h => dolfin/generation/UnitSquareMesh.h
    dolfin/generation/UnitTetrahedron.h => dolfin/generation/UnitTetrahedronMesh.h
    dolfin/generation/UnitTriangle.h => dolfin/generation/UnitTriangleMesh.h

  Note in particular that the classes Box and Rectangle now exists as csg shape
  classes. For the rest of the classes, deprecation classes with the old are still
  present.

* Introduction of size_t and removal of dolfin::uint