FEniCS updates

[johannesring]

• Update FEniCS to latest version 2016.1
• Explicitly add parameter empty_osx_deployment_target in base cmake package
• Add parameter cmake_osx_sysroot in base cmake package
• Add base package for installing python packages using pip
• Use cython tarball from github (old url broken)
• Add new FEniCS package dijitso
• Use install_name_tool to fix rpath for dolfin on macOS
• Add host packages for py and pip
• Add lapack to build dependencies for petsc
• Upgrade pip to version 8.0.3
• Add blas to dependencies for scipy
• Add parameter with_openblas to scipy for building with openblas (default is false)
• Add parameter vtk_wrap_python to allow vtk to be built without python interface