Log Message:
Update dvipdfmx to 20070518.

Changes since 20050831:
- Xref and object stream were implemented for PDF v1.5 or higher to reduce the
  size of the PDF output.
- New program "xbb" is included, which generates ".xbb" file \ 
containing the
  bounding box information. For bitmap images, DVIPDFMx generates the same
  result as pdfTeX if ".xbb" is used, and as DVIPDFM if \ 
".bb" is used.
- Many bug fixes.