do not add the "-Wl,--as-needed" linker flag in FindSuiteSparse.cmake

because if umfpack is fully linked but some other library is
underlinked, it causes the build to fail. This flag is better dealt
with in the "UseOnlyNeeded.cmake" module...
make the "-Wl,--as-needed" flag optional

as there is not much harm done if it is not used but it may cause the
build to fail if it is present (read: it causes _my_ build to fail),
it defaults to OFF.
convert the EclipseGridInspector to opm-parser

that one is completely unused in opm-core (*booo*!), but used quite a
bit in dune-cornerpoint and dune-porsol, so let's keep it for now...
CornerPointChopper: add methods opm-parser'y methods
add opm-parser variants for the incompressible property classes
remove the import_rewrite example

that one was quite specific to the old parser and would thus require
more work to convert to the opm-parser than what it is worth the
effort. If you _really_ want to keep this tool, ping me and I'll port
it...
convert the examples and the tests to opm-parser