Fix debugger not detaching when CPU entity is removed

[n1lordduck]

When a debugger is attached to a CPU entity, removing the entity does not currently detach the debugger. As a result, the debugger remains attached to a non-existent CPU, which can be confusing.

This PR ensures the debugger is properly detached when the CPU entity is removed, also creates a DetachDebugger method that removes the giant chunk of code in the original AttachDebugger method that was responsible for detaching it manually.

[DerelictDrone]

Works well, but in my testing detaching manually (by pressing R with the cpu tool) reports the detach message twice.
(first detached with no attached debugger, second attached, then detaching will produce two messages)

This is due to a second net send for invalidating the debugger within the stool's own file, present here:

wire-cpu/lua/wire/stools/cpu.lua

Lines 48 to 68 in 1113394

	if player:KeyDown(IN_SPEED) then
	if (trace.Entity:IsValid()) and
	(trace.Entity:GetClass() == "gmod_wire_cpu") then
	trace.Entity:SetMemoryModel(self:GetClientInfo("memorymodel"),self:GetClientInfo("customram"),self:GetClientInfo("customrom"))
	trace.Entity:FlashData({})
	net.Start("CPULib.InvalidateDebugger") net.WriteUInt(0,2) net.Send(player)
	end
	else
	if (not trace.Entity:IsPlayer()) and
	(trace.Entity:IsValid()) and
	(trace.Entity:GetClass() == "gmod_wire_cpu") then
	CPULib.AttachDebugger(trace.Entity,player)
	CPULib.SendDebugData(trace.Entity.VM,nil,player)
	net.Start("CPULib.InvalidateDebugger") net.WriteUInt(2,2) net.Send(player)
	else
	CPULib.AttachDebugger(nil,player)
	net.Start("CPULib.InvalidateDebugger") net.WriteUInt(1,2) net.Send(player)
	end
	end
	return true
	end

Once resolved, this should be ready for merge tomorrow.

[n1lordduck]

I believe I've fixed it!

[DerelictDrone]

Need to clear this flag and on remove hook during detach if possible, as deleting the CPU after detaching your debugger reports that it was detached(again), after that we should be good assuming nothing else crops up
https://github.com/wiremod/wire-cpu/pull/73/files#diff-7ef44bc4870f2b9b65b05f458388a300de8f00377bfa7430d5e5b7e5026ce3b7R617-R623

[n1lordduck]

Working on it

[n1lordduck]

I hope everthing is correct now.

[DerelictDrone]

Tested and working as intended.