Removes img max-width and height,

Resolves tailwindlabs#506.

Author: mvdnbrk

__tests__/fixtures/tailwind-output.css

@@ -463,11 +463,6 @@ textarea {
   resize: vertical;
 }
 
-img {
-  max-width: 100%;
-  height: auto;
-}
-
 input::placeholder,
 textarea::placeholder {
   color: inherit;

css/preflight.css

@@ -459,11 +459,6 @@ textarea {
   resize: vertical;
 }
 
-img {
-  max-width: 100%;
-  height: auto;
-}
-
 input::placeholder,
 textarea::placeholder {
   color: inherit;