Kowhai utils asserts

remove asserts from kowhai_utils
    
    some platforms don't implement all the std signal lib required to use
    assert (like _exit, _kill, etc), it would be nice if kowhai didnt depend
    on any of these ... it seems these asserts may just have been left there
    for development anyway so I think it is safe enough just to remove them
    since they are all on internal (static) functions and assume they wont
    happen