- dimensions flattening conversion only flattens packed dimensions
- conversion for packing arrays when necessary (preserves memories)
- added coverage for array with multiple packed dimensions
- test runner no longer forbids multi-dim accesses after conversion
- Decl and subordinate types derive Ord

This is the same as most compilers (e.g. gcc and clang) but also
verilog tools (e.g. yosys) output error mesasge in a standardized form.

This form can immediately be parsed by IDE tools that can jumping
through a list of error messages, placing the cursor at the given
file position.

This change simply re-arranges the error message printing to conform to that
standard.

Signed-off-by: Henner Zeller <h.zeller@acm.org>