Generate a code-signing certificate for signing XSH files

<xsharper xmlns="http://www.xsharper.com/schemas/1.0">
    <param name="subject">Certificate subject, for example "My Code Signing Cert"</param>
    <param switch="installRoot" count="none" unspecified="-1" default="0">Install this certificate as root</param>
    <usage options="default ifNoArguments" />
    <shell>makecert -r -pe -n "CN=${subject}" -e 01/01/2030 -eku 1.3.6.1.5.5.7.3.3 -ss my -sr currentUser -sky exchange -sp "Microsoft RSA SChannel Cryptographic Provider" -sy 12 "xsh-${subject}.cer"</shell>
    <if isNotZero="${installRoot}">
        <shell>certutil -addStore root "xsh-${subject}.cer"</shell>
    </if>
</xsharper>