Make exact matches win for path lookup

This fixes a bug where when a wildcard path is specified *after* an
exact path the wildcard would win.  The reason is that for/in loops go
in the order that the keys were defined. Deleting the key and readding
it shows the error. The fix is simply to break out the loop once we find
an exact match. Fixes #189

Author: matthewp

lib/system.js

@@ -235,8 +235,10 @@
 
           // exact path match
           if (pathParts.length == 1) {
-            if (name == p && p.length > pathMatch.length)
+            if (name == p && p.length > pathMatch.length) {
               pathMatch = p;
+              break;
+            }
           }
 
           // wildcard path match

test/test.js

@@ -388,7 +388,9 @@ function runTests() {
   });
 
   test('Custom path most specific', function(assert) {
+    delete System.paths['bar/*'];
     System.paths['bar/bar'] = 'loader/specific-path.js';
+    System.paths['bar/*'] = 'loader/custom-folder/*.js';
     System['import']('bar/bar').then(function(m) {
       assert(m.path, true);
     });