Initial work on issue #112

* Fix Python libs makefile for cross compile
* Create Makefile.modelsim so now can run example using make SIM=modelsim
Add very basic protocol check to packetised Avalon-ST monitor
More helpful debug message when yielding wrong objects to scheduler
Cleanup: Add WAVES=1 option to Aldec Makefile to create a full database
Fix table in endian_swapper documentation, add information about TestFactory
Prevent writing non-UTF-8 characters to XML
Issue #9: Start adding auto-generated documentation from docstrings
Issue #9: Move trigger documentation into library reference and autodoc
Issue #9 - add Driver, Monitor and Scoreboard to library reference
Don't fail silently if drivers don't implement _driver_send method
chmod -x on handle.py
Issue #113 add operators to BinaryValue
Issue #114: Fixes for IUS simulator makefile from @nicklfitz
Closes #107: Implement system tasks for reporting and fail the test on $fatal
Issue #117: Initial AXI4-Lite master implementation
Issue #116: Initial stab at VHPI layer (uncompiled!)
Cleanup: Improve initialisation reporting and remove duplicate warning message
Issue #116: Fix up VHPI errors using GHDL, add vhpi_user.h
Issue #116: Really add vhpi_user.h
Issue #116: Makefile for GHDL (not working)