Some tests are not applied for CreditNote type

[jarekglapski]

Some tests, like:
[UBL-SR-05]-Payment terms shall occur maximum once
and many more are not applied for CreditNote type, because the corresponding template matches only an Invoice:
<xsl:template match="/ubl:Invoice" mode="M11" priority="1006">

According to specs, at least some of them (ex: [UBL-SR-05]) should apply to CreditNotes as well.
I believe, all of them are "warnings", but perhaps it is worth to be refactored anyway.

[oriol]

The context has been changed to value="/ubl:Invoice | /cn:CreditNote" so this is resolved.