Add key mappings for `Kana`, `Eisu` and `Muhenkan`

src/lib/platform/MSWindowsKeyState.cpp

@@ -69,7 +69,7 @@ const KeyID				MSWindowsKeyState::s_virtualKey[] =
 	/* 0x01a */ { kKeyNone },		// undefined
 	/* 0x01b */ { kKeyEscape },		// VK_ESCAPE
 	/* 0x01c */ { kKeyHenkan },		// VK_CONVERT		
-	/* 0x01d */ { kKeyNone },		// VK_NONCONVERT	
+	/* 0x01d */ { kKeyMuhenkan },	// VK_NONCONVERT	
 	/* 0x01e */ { kKeyNone },		// VK_ACCEPT		
 	/* 0x01f */ { kKeyNone },		// VK_MODECHANGE	
 	/* 0x020 */ { kKeyNone },		// VK_SPACE

src/lib/platform/OSXKeyState.cpp

@@ -123,6 +123,10 @@ static const KeyEntry    s_controlKeys[] = {
     { kKeyLaunchpad, s_launchpadVK },
     { kKeyBrightnessUp,  s_brightnessUp },
     { kKeyBrightnessDown, s_brightnessDown }
+
+    // JIS keyboards only
+    { kKeyEisuToggle, kVK_JIS_Eisu },
+    { kKeyKana, kVK_JIS_Kana }
 };