Introducing the main window, yet more tweaks to localization support

locale/en-US.txt

@@ -6,6 +6,7 @@ locale {
 
 # Main window
 app {
+
   title {
     default     PVB Emulator
     mixed       {ctrl.number} {ctrl.filename} - {app.title.default}
@@ -16,6 +17,7 @@ app {
   file {
     (menu)      File
     load_rom    Load ROM...
+    new_window  New window
     exit        Exit
   }
 
@@ -30,3 +32,11 @@ core {
   windows-x86       Windows (32-bit)
   windows-x86_64    Windows (64-bit)
 }
+
+# File dialog
+dialog {
+  load              Load
+  load_rom          Load ROM
+  load_rom_error    Unable to load the selected ROM file.
+  load_rom_notvb    The selected file does not appear to be a Virtual Boy ROM.
+}