MFen and activate Japanese 4.6.2R-related docs:

1.51 -> 1.52 includes.sgml
1.7 -> 1.9 includes.xsl
1.25 -> 1.29 index.xsl
1.32 -> 1.35 releases/Makefile
1.76 -> 1.78 releases/index.sgml
(new) releases/4.6.2R/relnotes-alpha.html
(new) releases/4.6.2R/relnotes-i386.html