Protect against underlinking of UMFPACK library

If libumfpack.so does not declare an explicit dependency on libamd.so,
the linker option -Wl,--as-needed will cause an undefined reference
since we don't use libamd.so ourself. If the configuration determines
that this may be the case, a linker option that forces linking the the
AMD library is added for the SuiteSparse library, and the general
configuration then gets out of the way if this is set.
Merge pull request #150 from rolk/150_underlink

Link issues in release/2013.03 branch on CentOS 5.9
added: debian packaging control files
Copy test data to writable location at config time

Test data is made available in the output tree so that the tests can
run in a writable environment. Earlier this was done with a custom
target so that they were only copied on-demand before actually running
the tests. However, this caused trouble with the "test" magic CTest
target, as well as some versions of make, so the tests are now copied
at configuration time.