WIP: SPM permutations

Permute the arrays of a spm thanks to a permtab of size gN. This routine only works with one node for the moment

include/spm.h

@@ -143,6 +143,7 @@ int    spmMatMat( spm_trans_t trans, spm_int_t n,
                   double beta,        void *C, spm_int_t ldc );
 void   spmScalMatrix( double alpha, spmatrix_t *spm );
 void   spmScalVector( spm_coeftype_t flt, double alpha, spm_int_t n, void *x, spm_int_t incx );
+spmatrix_t *spmApplyPerm( spm_dir_t forward, const spmatrix_t *spm, const spm_int_t *permtab );
 
 /**
  * @}