Dune libraries are now preferentially looked for in the prefix/lib directory.
Removed some deprecation warnings emitted from BEM++ code.
Deprecated Space::basis() and GridFunction::basis() with a GCC attribute
(these functions have been superseded by ...::shapeset()).
Fixed tolerance in some tests of barycentric shapesets.
Merge branch 'release_2.0' of https://github.com/bempp/bempp into release_2.0