maps should not be directly output into css

[chriseppstein]

maps, like numbers with complex units, are never a value that can be understood by css, so ruby sass gives an error when this is attempted.

The following sass file:

$m: (a: 1, b: 2);

.foo {
  interpolated: "#{$m}";
  direct: $m;
  inspected: inspect($m);
}

in libsass compiles to:

.foo {
  interpolated: "(a: 1, b: 2)";
  direct: (a: 1, b: 2);
  inspected: (a: 1, b: 2); }

But an error should have been given. Only the third line, using the inspect function should have succeeded.