#438 Fail on bad olink parameter

[David Cramer]

I would like there to be a fail.on.bad.olink parameter so that I can easily break the build if an olink can't be resovled. In my customization layer, I plan to add <xsl:if test="$fail.on.bad.olink != 'no'"><xsl:message terminate="yes"/></xsl:if> immediately after the olink-related messages that convey really bad news.