STYLE: IOstreams with float/double instead of floatScalar/doubleScalar

- consistent with defining IO of int32_t/int64_t and with recent
  changes to ensightFile. Using the primitives directly instead of
  typedefs to them makes the code somewhat less opaque.

applications/test/matrices/RectangularMatrix/Test-RectangularMatrix.C

@@ -44,8 +44,7 @@ Note
 
 #include "RectangularMatrix.H"
 #include "SquareMatrix.H"
-#include "floatScalar.H"
-#include "doubleScalar.H"
+#include "scalar.H"
 #include "complex.H"
 #include "IOmanip.H"
 #include "TestTools.H"