• Merge the following from the English version:

1.55 -> 1.58 Makefile
1.95 -> 1.100 index.sgml
1.201 -> 1.206 support.sgml
1.88 -> 1.91 projects/projects.sgml
1.55 -> 1.58 search/search.sgml
1.17 -> 1.18 tutorials/index.sgml

• Add &enbase; into "prehtml" script to support not-translated docs. This was defined in ja/tutorials/index.sgml only.
  
  Prehtml now requires at least two arguments "localtop" and "relative path from localtop". Using prehtml w/ and w/o a option -revcheck, we don't need a definition of &base; in individual SGML files because prehtml generates it automatically (of course, it doesn't break build process of conventional docs).