Macros not found in Sparql Update Statements.

[Aklakan]

Macros are detected and expanded in SPARQL queries but not in SPARQL update statements.

The issue was fixed by using StmtTransform rather than QueryTransform: cfe2c2f

We still need to add couple of tests to ensure this is now working as expected.

[Aklakan]

A note about what to test:

In Jena, custom function registries in the query exec context were not forwarded to the update request before apache/jena#2822
I don't think macros were affected because:

• I think functions registered globally to the ARQ context worked before though.
• Macro expansion is implemented as an algebraic preprocessing step using an RdfDataSource wrapper - so it happens before the conventional Jena machinery.

But in any case, the test cases to be added need to check macros that make use of custom functions in both query and update statements.