Big memory leak in CL_PNGProvider::save

[FluXy]

Based on the latest SVN (1350).


The function

png_destroy_write_struct( &png_ptr, &info_ptr );
should be called after

png_write_end(png_ptr, info_ptr);
to destroy the write and info struct :)

[rombust]

Well spotted :)

Applied patch to 0.8 and 0.9 SVN

Many Thanks.