hgmerge: various cleanups Details: - put temporary file names into variables - make all temporary file names end with random part - cleanup FileMerge handling - do not use hardlinks in FileMerge change test (breaks on FAT) - try harder to keep file mtime unchanged in case of failed merge

<item>
    <title>#desc|strip|firstline|strip|escape#</title>
    <link>#url#?f=#filenode|short#;file=#file|urlescape#</link>
    <description><![CDATA[#desc|strip|escape|addbreaks#]]></description>
    <author>#author|obfuscate#</author>
    <pubDate>#date|rfc822date#</pubDate>>
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