hgmerge: fix diff+patch detection; cleanups Details: - actually show help message when no tools are found - whitespace cleanup (stupid emacs) - quote more variables - simplify merge/diff3 error handling

default = "changelog"
header = header-rss.tmpl
changelog = changelog-rss.tmpl
changelogentry = changelogentry-rss.tmpl
filelog = filelog-rss.tmpl
filelogentry = filelogentry-rss.tmpl