Text: properly compute glyph count in FreeTypeFont layouter.

It was the same as byte count, thus working only for pure ASCII, not
UTF-8.

src/Text/FreeTypeFont.cpp

@@ -194,12 +194,12 @@ namespace {
 FreeTypeLayouter::FreeTypeLayouter(FreeTypeFont& font, const Float size, const std::string& text): font(font), size(size) {
     /* Get glyph codes from characters */
     glyphs.reserve(text.size());
-    _glyphCount = text.size();
     for(std::size_t i = 0; i != text.size(); ) {
         UnsignedInt codepoint;
         std::tie(codepoint, i) = Corrade::Utility::Unicode::nextChar(text, i);
         glyphs.push_back(FT_Get_Char_Index(font.font(), codepoint));
     }
+    _glyphCount = glyphs.size();
 }
 
 std::tuple<Rectangle, Rectangle, Vector2> FreeTypeLayouter::renderGlyph(const Vector2& cursorPosition, const UnsignedInt i) {