Non existent / Non valid url crashes application on Windows

[lmfff]

Using this workaround #7 (comment) for having REST-love work on Windows
I get this error with README SimpleExample 's when getting non existent / non valid url

Error: Thread error (Thread: 0x01c2cdc66900)

string:24: attempt to index local 'resp' (a boolean value)
stack traceback:
        string:24: in function '_WIN_REST'
        string:41: in main chunk
stack traceback:
        [string "boot.lua"]:777: in function <[string "boot.lua"]:773>
        [C]: in function 'error'
        [string "boot.lua"]:631: in function <[string "boot.lua"]:630>
        [string "boot.lua"]:604: in function <[string "boot.lua"]:594>
        [C]: in function 'xpcall'

[lmfff]

This seems to be solved by editing the _WIN_REST function in rest-lib/win-rest.lua

This:

if(isHead) then
    return resp.raw_headers
else
    return resp.body
end

could be changed to this:

if resp then
    if(isHead) then
        return resp.raw_headers
    else
        return resp.body
    end
else
    return false
end

To avoid indexing "resp" when it is a boolean value (false). I also return false if resp is false.
This needs to be changed both in the function declaration and when creating the thread with this function.