B-Em with VDFS Changing Length Fix.

windows: Avoid setting compiler in Makefile.win

The Makefile.win makefile is used both from makebem.bat for native
compilation under MingW and from mkcross.sh for cross-compilation on
Linux but the compilers are typically named differently in these two
cases.

This commit removes defining the compiler from Makefile.win and relies
on the calling shell script to set for the task in hand.

B-Em with Preliminary HFE Support and the Turbo 6502 Tube

This is cross compiled for Windows from the latest master as of the date of release. This release includes support for HFE and IMD floppy image formats and support for the Turbo version of the 6502 end processor as used internally within Acorn for assembling large programs. Also various bug fixes.

Debugger Symbols and LEDs

This pre-release includes the work Dominic Beesley has been doing on symbols within the debugger (new command symbol within the debugger) and also work from ZornsLemma to add optional display of the various LEDs (see Settings/Video).

Music 5000 Optimisation

This is pre-release, built for Windows, of dp11's Music 5000 optimisation that started with a Raspberry Pi. See https://stardot.org.uk/forums/viewtopic.php?f=2&t=19038

Integra B with Issues#92 and #93 Fixed

This adds fixes to two issues around ROM handling.
#92 ROM configuration is not saved when switching models.
#93 ROM menu RAM indication and RAM tickbox on sub-menu are sometimes out of step.

Integra B emulation with the reset issue fixed.

See https://stardot.org.uk/forums/viewtopic.php?f=4&t=17675&p=249181#p248995

PDP11 Emulation

This release includes an emulated PDP11 co-processor and includes pre-built versions for Windows.

68000 co-processor

This includes an emulation of a 68020 as a co-processor using Musahi for the 68000. Pre-built Windows versions are included.

Testing Issue90/Issue91

This is a windows build of the sf/issue90 release for testing in connection with Issue 91.

Integra Preview

This is a release of the sf/integra branch which adds emulation of the Integra B board to B-Em. This appears to work but has received very little testing. It is more for experimentation and further testing than serious use.