osutil: fold stat paths together
- simplify st/py_st logic
- use stp to point to stat buffer
- combine stat paths
default = 'changelog'
feedupdated = '<updated>#date|rfc3339date#</updated>'
header = header.tmpl
changelog = changelog.tmpl
changelogentry = changelogentry.tmpl
filelog = filelog.tmpl
filelogentry = filelogentry.tmpl
tags = tags.tmpl
tagentry = tagentry.tmpl