Update CHANGELOG with changes so far
Fix copy paste typo in swap_byte_order
Fix use after free in menu_entry_frame_free
Use GString for appending strings

It can take a very long time to print a _NET_WM_ICON property for firefox with the previous code, several minutes. Fixes bug #6042 and also implements the change for append_string.
Fix compile failure when X_HAVE_UTF8_STRING is not defined
Use PANGO_UNDERLINE_SINGLE for rendering shortcuts

The pango docs say to use _LOW for accelerators, but that causes the line
to be drawn beneath the ink extents which for us may be outside the area
that gets displayed and we end up with no line at all. We also don't want
to extend every menu entry with enough space to fit this possible line.