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/btl/libs/eigen2/eigen2_interface.hh

@@ -218,7 +218,7 @@ public :
   }
 
   static inline void partial_lu_decomp(const gene_matrix & X, gene_matrix & C, int N){
-    C = X.partialLu().matrixLU();
+    C = X.partialPivLu().matrixLU();
   }
 
   static inline void tridiagonalization(const gene_matrix & X, gene_matrix & C, int N){