XSLT checker to use xsltproc

[MasseR]

Consider changing xslt checker to use xsltproc instead of xmllint.

Example output:

compilation error: file file.xsl line 21 element alue-of
xsltStylePreCompute: unknown xsl:alue-of

It also returns xmllint style errors for xml errors:

file.xsl:21: parser error : expected '>'
                <fo><xsl:value-of select="$asd" /></foo>

Invoked with xsltproc file.xsl

[lcd047]

Consider changing xslt checker to use xsltproc instead of xmllint.

Working PRs are welcome. I believe I did look at xsltproc sources a while ago, and I gave up. If I recall correctly the possible error messages are essentially too hostile to parsing.

It also returns xmllint style errors for xml errors:

This is to be expected, they are both using the same library for validation.