Relative translations are not loaded in the proper locale (#54)

* Relative translations are not loaded in the proper locale

e.g. if you have a file:
```PHP
<?php
return [
    ‘key’ => __(‘other_file.other_key’),
];
```
it is translated to the base locale and not the current locale, this
should fix that.

* updated so tests don't fail

since the unit tests aren’t run inside of Laravel scope, this will
check that App is available before calling setLocale on it.

src/Generator.php

@@ -59,6 +59,9 @@ public function generateFromPath($path, $umd = null, $withVendor = false)
             $fileinfo = new \SplFileInfo($fileName);
 
             $noExt = $this->removeExtension($fileinfo->getFilename());
+            if (class_exists('App')) {
+                App::setLocale($noExt);
+            }
 
             if ($fileinfo->isDir()) {
                 $local = $this->allocateLocaleArray($fileinfo->getRealPath());
@@ -113,8 +116,10 @@ public function generateMultiple($path, $umd = null)
                 && !in_array($fileinfo->getFilename(), ['vendor'])
             ) {
                 $noExt = $this->removeExtension($fileinfo->getFilename());
-                if (!in_array($noExt, $this->availableLocales)) {
+                if (class_exists('App')) {
                     App::setLocale($noExt);
+                }
+                if (!in_array($noExt, $this->availableLocales)) {
                     $this->availableLocales[] = $noExt;
                 }
                 if ($fileinfo->isDir()) {