big huge changes, so i dont remember everything.

* renaming, e.g. LU ---> FullPivLU
* split tests framework: more robust, e.g. dont generate empty tests if a number is skipped
* make all remaining tests use that splitting, as needed.
* Fix 4x4 inversion (see stable branch)
* Transform::inverse() and geo_transform test : adapt to new inverse() API, it was also trying to instantiate inverse() for 3x4 matrices.
* CMakeLists: more robust regexp to parse the version number
* misc fixes in unit tests

bench/sparse_lu.cpp

@@ -98,7 +98,7 @@ int main(int argc, char *argv[])
 
       BenchTimer timer;
       timer.start();
-      LU<DenseMatrix> lu(m1);
+      FullPivLU<DenseMatrix> lu(m1);
       timer.stop();
       std::cout << "Eigen/dense:\t" << timer.value() << endl;