merge: only store one direction of copies in the copy map
simplify checkpair
generate copied hash from copy map
make copy cases more symmetrical
header = header.tmpl
footer = ''
changeset = changeset.tmpl
difflineplus = '#line#'
difflineminus = '#line#'
difflineat = '#line#'
diffline = '#line#'
changesetparent = '# Parent #node#'
changesetchild = '# Child #node#'
filenodelink = ''
filerevision = '#rawfileheader##raw#'
fileline = '#line#'
diffblock = '#lines#'
filediff = filediff.tmpl
fileannotate = fileannotate.tmpl
annotateline = '#author#@#rev#: #line#'