Stylus syntax highlight (#81)

Add syntax highlight to all block code examples

readme.md

@@ -204,7 +204,7 @@ All you need to do to enable this behavior is to define an optional `rupture.bas
 
 Example:
 
-```
+```styl
 // base-font-size = 18px (commented out because it's optional and we want 16px)
 rupture.enable-em-breakpoints = true
 
@@ -237,7 +237,7 @@ You can prevent scale slices from overlapping with neighbouring slices by settin
 
 Alternatively, you can set `rupture.anti-overlap` to `true` or any falsy value, which are equivalent to `1px` and `0px`, respectively. Here are some examples:
 
-```js
+```styl
 rupture.anti-overlap = false // default value
 rupture.anti-overlap = true // enables 1px (or em equivalent) overlap correction globally
 rupture.anti-overlap = 0px // same as rupture.anti-overlap = false
@@ -249,7 +249,7 @@ rupture.anti-overlap = 1px 0.0625em 0.0625rem // explicit relative values will b
 
 If you don't want to enable anti-overlapping globally, you can enable or disable it locally by passing the `anti-overlap` keyword argument to any of the mixins except `retina()`. This works exactly like the global `rupture.anti-overlap` variable, except you can specify it per mixin call. For example:
 
-```
+```styl
 .overlap-force
   text-align center
   +at(2, anti-overlap: true)
@@ -276,7 +276,7 @@ The `anti-overlap` offset list may contain positive or negative values. Positive
 
 For example, with a positive offset:
 
-```
+```styl
 rupture.scale = 0 400px 800px 1200px
 rupture.anti-overlap = 1px
 
@@ -307,7 +307,7 @@ rupture.anti-overlap = 1px
 
 With a negative offset (and em breakpoints):
 
-```
+```styl
 rupture.scale = 0 400px 800px 1200px
 rupture.anti-overlap = -1px
 rupture.enable-em-breakpoints = true
@@ -345,7 +345,7 @@ Every Rupture mixin accepts an optional `fallback-class` argument that makes it
 easy to augment behavior for browsers that do not support media queries. For example
 the following code will produce the commented result below:
 
-```
+```styl
 .ui-element
   color: blue
   +above(500px, fallback-class: '.lt-ie9')