Actually, we need to increase the size of BUFSIZE, not just the size of _buffer....

Actually, we need to increase the size of BUFSIZE, not just the size of _buffer.  The previous patch might have cause problems if, for instance, state->free_in_buffer was 127 but 129 bytes were compressed.  In that case, only 127 of the 129 bytes would have been written to the file.  Also document the fix.

git-svn-id: svn+ssh://svn.code.sf.net/p/libjpeg-turbo/code/branches/1.3.x@1366 632fc199-4ca6-4c93-a231-07263d6284db