Check all deprecated features for 1.5 release

[Chris Richardson]

Update lines like this:

   #else
    warning("PETScMatrix may not be initialized more than once. In version > 1.4, this will become an error.");
    #endif

[Prof Garth Wells]

We should automate this, e.g. when the DOLFIN_DEPRECATION_ERROR=true throw a compile error.

From Python, we should be using dolfin.deprecation to get a runtime error.

[Prof Garth Wells]

Removing milestone: 1.5 (automated comment)