Organise the code base

[tomcl]

Describe the bug

The code should be better documented and factored into namespaces above module level

Expected behavior

• We should have XML descriptions of every module for the API docs.
• We should divide modules into namespaces roughly according to the current subdirectory structure, e.g:
  • EEExtensions
  • Common
  • UART
  • Interface
  • Model
  • Draw
  • Simulator
  • Verilog
  • UI
  • Truthtable
  • WaveSim
  • Main (includes all the update-related modules and UI/mainview)
• Reorganise folders so namespace = folder

[tomcl]

Renaming types

We should rename the SymbolT, BusWireT, SheetT Model types as SymModel WireModel, DrawModel.

We should refactor Model types a bit more to organise fields and reduce top-level size.

We should refactor Symbol update like BusWire update to allow it to change the whole Model.

This must be done when no-one else is working on Issie!