Support MS-Windows build and reversed rows in GUI frames; add initial docs.

Support MS-Windows build and reversed rows in GUI frames; add initial docs.

 doc/emacs/mule.texi (International): Mention support of
 bidirectional editing.
 (Bidirectional Editing): New section.
 etc/HELLO: Reorder Arabic and Hebrew into logical order, and
 insert RLM before the opening paren, to make the display more
 reasonable.  Add setting for bidi-display-reordering in the local
 variables section.
 lisp/files.el: Make bidi-display-reordering safe variable for
 boolean values.
 src/xdisp (append_glyph): If the glyph row is reversed, prepend the
 glyph rather than appending it.
 src/makefile.w32-in (OBJ1): Add $(BLD)/bidi.$(O).
 ($(BLD)/bidi.$(O)): New target.