LUA based Timer implementation

[SukuWc]

Add the following code to system element's setup event to test:

local timer1 =
    set_timeout(
    function(timer)
        print("Timer" .. timer.id .. ": 1 second elapsed" .. os.clock())
        return true
    end,
    1
)
local timer2 =
    set_timeout(
    function(timer)
        print("Timer" .. timer.id .. ": 2 seconds elapsed" .. os.clock())
        return true
    end,
    2
)
timer_start(self:element_index(), 100)