refactoring
 - set default value to global variables
 - added s:PW_valid_config()
 - added s:PW_is_init()
removed :global, :substitute
refactoring
 - added s:PW_insert_header()
 - added s:PW_yesno()
- fixed a bug when we reload an attached list
- refactoring
-- added s:pukiwiki_header_row
added unite/attach
added pukiwiki#update_digest()
added s:set_password()
change the behavior when update failed
refactoring
 - remove unsed variables
 - change b: variables to a dictionary
refactoring
 - remove variable enc_page
 - iconv is done only in PW_write, PW_req
refactoring
 - check "enc"
 - remove unnecessary calling
remove comments
convert fileencoding to utf-8
removed pukiwiki#say_hello()
use setline() in order to insert document
  - remove 'execute "normal! i" . body'
use setpo()
 - removed 'execute "normal! gg"'
fixed a bug.
  - keep empty line
support anchor / &aname()
use search() in move_next|prev_brancket()