fix(input-container): prefix and suffix stretching together with parent

Prevents the input's suffix and prefix from stretching together with their parent node and leaving some weird spacing between themselves and the input. This was a side-effect of using `display: table-cell`.

Fixes #2493.
Fixes #1881.
Fixes #1421.

Author: crisbeto

src/lib/input/input-container.scss

@@ -30,3 +30,9 @@ md-input-container {
     }
   }
 }
+
+// Prevents the prefix and suffix from stretching together with the container.
+.md-input-prefix, .md-input-suffix {
+  width: 0.1px;
+  white-space: nowrap;
+}