Be more flexible about version number quoting

Some versions of libtool write quotes around the version number, some
do not; we must handle both cases.
Strict option checking unless otherwise specified

Having option checking catches typos. Disabling the checking enable us
to use the same build options for a bunch of packages even though they
may not have the same dependencies.
Use more functions in testing found umfpack

The HAVE_UMFPACK_WITHOUT_CHOLMOD test would generate a false success.
New test contains program with more calls to the umfpack API, reflecting
our actual usage.
Merge remote-tracking branch 'upstream/cmake' into cmake
Add 'examples' make target.

Also, make sure some examples and tutorials are only conditionally compiled.