- Feature #153: Introduce FiniteElementSpace from former DofManager. This class sotres the finite element; tuple of global operators are therefore no longer relevant. - Feature #146: Introduce a proto-Domain and apply it in operators. - Support #137: Petsc has been upgraded to 3.5. As usual, new version is not backward-compatible and few modifications have thus been reported in the code. - Design #128: Prepare UML(s) for Geometry. The code has been slightly modified in the process. - Support #130: Define a typedef to use a more user-friendly syntax to feed vectors and matrices to global operators. - Support #140: Refactoring/clean-up of Model, VariationalFormulation and their inherited classes in elastic and hyperelastic problems. - Bug #136: now the class that can access and modify Petsc Vector (renamed AccessVectorContent) respects constness.