Remote exploitable crash on win32

[Eion Robb]

Just now was a user in #pidgin who managed to trigger a remote crash on my
windows system through what looks like a Pango glyph error.  I've attached
the html file (renamed as htmlx since viewing the history caused crashes
too) of the log that was causing the crashes.

Nothing appears in the Pidgin crash RPT dump file but there is a single
line in the debug log:
Pango:ERROR:basic-win32.c:485:convert_log_clusters_to_byte_offsets:
assertion failed: (glyphs->log_clusters[glyphix] < n_chars)

In the html log file, there appears to be an invisible character on line 9
at offset 81
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