Rewrite test/unit_test_io.jl with new fuselage/wing/tail

[aditeyashukla]

@argonaut22 IO unit test doesn't work because of new fuselage (and soon wing/tail)
we can fix this when wing/tail is pushed as you would have to fix it then too (If you want to get a head start you can pull the branch wing_remodel on my branch)

[askprash]

Left some suggestions and caveats here:

TASOPT.jl/src/IO/quicksave_load.jl

Lines 22 to 26 in d2d9b34

	acdict = struct2dict(ac)
	## But this works for the output portion but need to be *very* careful in reading it.
	# The dictionary stores by sorting the hash or something so the order is going to be different
	# So the only way to effectively load this would be to enforce kwargs explicitly either
	# by ensuring all the structs are defined with the @kwargs macro or an explicit kw constructor is provided.

and here:

TASOPT.jl/src/IO/quicksave_load.jl

Lines 108 to 123 in d2d9b34

	function struct2dict(obj)
	type = typeof(obj)
	# println("T = $type")
	d = Dict()
	for key ∈ fieldnames(type)
	# println("field = $key")
	if fieldtype(type, key) <: Union{AbstractArray,Number,String}
	# println("pushing...")
	push!(d, key => getfield(obj, key))
	else
	# println("recursing...")
	push!(d, key => struct2dict(getfield(obj, key)))
	end
	end
	return d
	end