* allow matrix dimensions to be 0 (also at compile time) and provide a specialization

of ei_matrix_array for size 0
* adapt many xprs to have the right storage order, now that it matters
* add static assert on expressions to check that vector xprs
  have the righ storage order
* adapt ei_plain_matrix_type_(column|row)_major
* implement assignment of selfadjointview to matrix
  (was before failing to compile) and add nestedExpression() methods
* expand product_symm test
* in ei_gemv_selector, use the PlainObject type instead of a custom Matrix<...> type
* fix VectorBlock and Block mistakes

Eigen/src/Array/Replicate.h

@@ -55,7 +55,10 @@ struct ei_traits<Replicate<MatrixType,RowFactor,ColFactor> >
                       : ColFactor * MatrixType::ColsAtCompileTime,
     MaxRowsAtCompileTime = RowsAtCompileTime,
     MaxColsAtCompileTime = ColsAtCompileTime,
-    Flags = (_MatrixTypeNested::Flags & HereditaryBits),
+    IsRowMajor = RowsAtCompileTime==1 && ColsAtCompileTime!=1 ? 1
+               : ColsAtCompileTime==1 && RowsAtCompileTime!=1 ? 0
+               : (MatrixType::Flags & RowMajorBit) ? 1 : 0,
+    Flags = (_MatrixTypeNested::Flags & HereditaryBits & ~RowMajorBit) | (IsRowMajor ? RowMajorBit : 0),
     CoeffReadCost = _MatrixTypeNested::CoeffReadCost
   };
 };