Add util.splitpath() and use it instead of using os.sep directly.
This change is intended to allow hooking splitpath() by win32mbcs
extension for MBCS support.
default = 'changelog'
header = header.tmpl
changelog = changelog.tmpl
changelogentry = changelogentry.tmpl
filelog = filelog.tmpl
filelogentry = filelogentry.tmpl
tags = tags.tmpl
tagentry = tagentry.tmpl