localrepo: improve readability of _findtags(), readtags() (issue548).
- rename many local variables
- add some comments
- refactor call to line.split() (catch ValueError rather
than checking length of return value: one less local variable)
default = 'changelog'
feedupdated = '<updated>{date|rfc3339date}</updated>'
mimetype = 'application/atom+xml; charset={encoding}'
header = header.tmpl
changelog = changelog.tmpl
changelogentry = changelogentry.tmpl
filelog = filelog.tmpl
filelogentry = filelogentry.tmpl
tags = tags.tmpl
tagentry = tagentry.tmpl
error = error.tmpl