Change global variables defined in any function to be defined in module

[mattsignorelli]

E.g. instead of

module A
  function setval(x)
    global a = x
  end
end

which is type unstable, we do

module A
  a::Float64 = NaN
  function setval(x)
    A.a = x
  end
end

[lllx125]

Done in branch 88 defined global variables with type Float64 and initialized them with NaN.