Merge branch 'develop'

Tagging as v0.5.0 as well. Hardware is solid again. Lots of software
subprojects in progress, but that's an eternal state.
Remove old html file from root
Add broken cases for unary test
Enable vga constraint ; constraint cosmetics
Scrap duplicate .coe and update build
Update Fibonacci test code

Initialise first 32 characters of VRAM in software to ensure we don't
combine with existing garbage after a soft reset. Disable hardware
cursor.
Build and refer to fib.coe explicitly
Update fib test code to extend VGA output

Currently not working as intended on hardware, although all output is
visible ; code is intended to build columns of N,fib(N) pairs, but
output still is overwritten (with some other artifacts). Suspect
multiplier unit, will pursue in simulation.
Explicitly zero registers in fib test
Register file always enable (mending race)
Printing hex and decimal numbers
Mend win32 build ; install libs
Add optional emulated 7-segment display

Use SDL to display a 4-digit 7-segment display like the one on the
Nexys3 board. Next is an 80x40 VGA display.
Preliminary SDL VGA device working

Doesn't respect controls, doesn't have a cursor.

This will only work if ram.h is adjusted so that VRAM and RAM do not
overlap. This probably means device lookup needs to be reworked, or
there needs to be a more sophisticated memory map.

The font.png was made with nafe2png (https://gist.github.com/4652192),
NAFE (http://nafe.sourceforge.net/), and the font used by the RTL
(http://www.javiervalcarce.eu/wiki/VHDL_Macro:_VGA80x40).
Optionally wait for a keystroke on illegal

This is intended to keep SDL windows from disappearing immediately, but
the keystroke is read from a stream (not via SDL), so if it isn't
`enter` it will likely need to be followed by one. Probably should
replace this with an SDL-specific recipe.
Initialise userdata pointer in case of no f->init
Correct name for iMPACT config file
Multiplier diagnostic WIP
Update project files to ISE 14.4
Reduce static and dynamic instruction count

Also regularise video address loading in disable_cursor.