Downloads page overhauled

[paulsoulsby]

The downloads page has now been overhauled and features V2 of the software.
Atmegatron users with software versions 1.0-1.4 (i.e. serial numbers < 1000), should install the EEPROM converter before installing the new software.
Atmegatron users with serial numbers > 1000 only need to install this software if they would like to return their Atmegatron to standard software after experimenting with other software versions.