Update to ensure plug-ins are used over files

This update ensures plug-ins (`remark-$foo`) are preferred over
files or directories (`$foo`, `$foo.js`, `node_modules/$foo`, &c.)

This became problematic for plug-ins like `remark-license`, as a file
named `LICENSE` is often available.  Or, for users with other similar
named non-plugins.

Closes GH-158.
Closes GH-160.

Author: wooorm

lib/cli/file-pipeline/configure.js

@@ -72,23 +72,17 @@ function findRoot(base) {
 /**
  * Require a plugin.  Checks, in this order:
  *
+ * -  `$package/node_modules/remark-$pathlike`;
+ * -  `$cwd/node_modules/remark-$pathlike`;
+ * -  `$modules/remark-$pathlike` (if global).
  * -  `$package/$pathlike`;
  * -  `$package/$pathlike.js`;
  * -  `$package/node_modules/$pathlike`;
- * -  `$package/node_modules/remark-$pathlike`;
  * -  `$cwd/node_modules/$pathlike`;
- * -  `$cwd/node_modules/remark-$pathlike`;
- * -  `$pathlike`.
+ * -  `$modules/$pathlike` (if global);
  *
- * Where `$package` is an ancestral package directory.
- *
- * When using a globally installed executable, the
- * following are also included:
- *
- * -  `$modules/$pathlike`;
- * -  `$modules/remark-$pathlike`.
- *
- * Where `$modules` is the directory of globally installed
+ * Where `$package` is an ancestral package directory,
+ * and `$modules` is the directory of globally installed
  * npm packages.
  *
  * @see https://docs.npmjs.com/files/folders#node-modules
@@ -111,19 +105,23 @@ function findPlugin(pathlike, cwd) {
     var plugin = pathlike;
     var length;
     var paths = [
+        resolve(root, MODULES, pluginlike),
+        resolve(cwd, MODULES, pluginlike)
+    ];
+
+    if (isGlobal) {
+        paths.push(resolve(globals, pluginlike));
+    }
+
+    paths.push(
         resolve(root, pathlike),
         resolve(root, pathlike + '.js'),
-        resolve(root, MODULES, pluginlike),
         resolve(root, MODULES, pathlike),
-        resolve(cwd, MODULES, pluginlike),
         resolve(cwd, MODULES, pathlike)
-    ];
+    );
 
     if (isGlobal) {
-        paths.push(
-            resolve(globals, pathlike),
-            resolve(globals, pluginlike)
-        );
+        paths.push(resolve(globals, pathlike));
     }
 
     length = paths.length;

package.json

@@ -90,6 +90,7 @@
     "jscs-jsdoc": "^1.0.0",
     "mocha": "^2.0.0",
     "remark-comment-config": "^3.0.0-alpha.1",
+    "remark-license": "^2.0.0-alpha.1",
     "remark-github": "^4.0.1",
     "remark-html": "^3.0.0-alpha.2",
     "remark-lint": "^2.0.0",