TitleManager: fix handling of title string

Truncate the title at the first occurrence of \0, as title strings
should be null-terminated.

Fixes #2219 (Weird characters on DSi Title Manager on melonDS 1.0RC)

src/frontend/qt_sdl/TitleManagerDialog.cpp

@@ -119,6 +119,7 @@ void TitleManagerDialog::createTitleItem(u32 category, u32 titleid)
 
     // TODO: make it possible to select other languages?
     QString title = QString::fromUtf16(banner.EnglishTitle, 128);
+    title = title.left(title.indexOf('\0'));
     title.replace("\n", " · ");
 
     char gamecode[5];