docs(readme): add documentation for global options

Author: Xiphe

readme.md

@@ -26,9 +26,12 @@ Add in your `.babelrc`
           "type": "element",
           "name": "button",
           "priority": 100,
-          "source": "./myButtonDirective.js"
+          "source": "./myButtonDirective.js",
+          "globalOptions": {
+            "colour": "fuchsia"
+          }
         },
-        "directive-module",
+        ["directive-module", { "colour": "pink" }],
         "path/to/a/directiveConfiguration.js"
       ]
     }]
@@ -51,6 +54,7 @@ _* Not really mandatory, but this plugin wont do nothing without specific config
  - `type` ("attribute"|"element"): whether the directive should be applied
    on matches against element names or attribute names. Default: "attribute"
  - `priority` (Integer): Directives with a higher priority run first, Default: 0
+ - `globalOptions` (any): Additional options that are provided to directives
  - `transformOptions` (Function): Only for attribute directives. Optional transformer
    for the options node. See [Transform Options](#transform-options)
 
@@ -142,6 +146,10 @@ target library, like [context](https://facebook.github.io/react/docs/context.htm
   A directive can also decide to not call `next` at all and prevent creation
   of all child components.
 
+- `globalOptions`: Globally provided directive options
+
+  see [Directive Configuration](#directive-configuration).
+
 - `options`: Value of the directive attribute. _(Only available on attribute directives)_
 
   Given this jsx `<div foo="bar" />`, a `foo` attribute directive would receive