No other state callbacks get called if theres no update

[josh-perry]

local Gamestate = require("hump.gamestate")

local ingame = {}

function ingame:draw()
    love.graphics.print("Hello, World!", 10, 10)
end

--

function love.load()
    Gamestate.switch(ingame)
end

function love.update(dt)
    --Gamestate.update(dt)
end

function love.draw()
    Gamestate.draw()
end

This code silently doesn't work. The state callbacks are completely ignored unless theres an update first, which seems to be intentionalish (#46). Uncommenting Gamestate.update works as expected.

hump/gamestate.lua

Line 102 in 08937cc

-- call function only if at least one 'update' was called beforehand

The fix for #46 really needs to be reverted, it causes this bug as well as the infamous single black screen (see: #46 (comment)) bug when switching states.