fix import external

src/app.js

@@ -217,6 +217,21 @@ This instance of Remix you are visiting WILL NOT BE UPDATED.\n
 Please make a backup of your contracts and start using http://remix.ethereum.org`)
   }
 
+  function importExternal (url, cb) {
+    handleImports.import(url,
+      (loadingMsg) => {
+        $('#output').append($('<div/>').append($('<pre/>').text(loadingMsg)))
+      },
+      (error, content, cleanUrl, type, url) => {
+        if (!error) {
+          filesProviders[type].addReadOnly(cleanUrl, content, url)
+          cb(null, content)
+        } else {
+          cb(error)
+        }
+      })
+  }
+
   // ----------------- Compiler -----------------
   var compiler = new Compiler((url, cb) => {
     var provider = fileManager.fileProviderOf(url)
@@ -226,22 +241,11 @@ Please make a backup of your contracts and start using http://remix.ethereum.org
         if (exist) {
           return provider.get(url, cb)
         } else {
-          return cb('Unable to import "' + url + '": File not found')
+          importExternal(url, cb)
         }
       })
     } else {
-      handleImports.import(url,
-      (loadingMsg) => {
-        $('#output').append($('<div/>').append($('<pre/>').text(loadingMsg)))
-      },
-      (error, content, cleanUrl, type, url) => {
-        if (!error) {
-          filesProviders[type].addReadOnly(cleanUrl, content, url)
-          cb(null, content)
-        } else {
-          cb(error)
-        }
-      })
+      importExternal(url, cb)
     }
   })
   var offsetToLineColumnConverter = new OffsetToLineColumnConverter(compiler.event)