localization: Use path relative to the application executable

This allows the languages to be loaded when the user is
running the app from another directory (e.g. when the app
is run from an exported path).

src/Application.cpp

@@ -30,7 +30,9 @@ Application::Application(int& argc, char** argv) :
 
     // First of all try to load the application translation file.
     m_translatorApp = new QTranslator(this);
-    ok = m_translatorApp->load("sqlb_" + name, "translations");
+    ok = m_translatorApp->load("sqlb_" + name,
+                               QCoreApplication::applicationDirPath() + "/translations");
+
     if (ok == true) {
         PreferencesDialog::setSettingsValue("General", "language", name);
         installTranslator(m_translatorApp);

src/PreferencesDialog.cpp

@@ -265,7 +265,9 @@ void PreferencesDialog::removeExtension()
 
 void PreferencesDialog::fillLanguageBox()
 {
-    QDir translationsDir("translations", "sqlb_*.qm");
+    // Use the path relative to the main executable
+    QDir translationsDir(QCoreApplication::applicationDirPath() + "/translations",
+                         "sqlb_*.qm");
 
     // Add default language
     ui->languageComboBox->addItem("English (United States)", "en_US");