I can't think of any reason to update signal flags if thread was already waiting
for the specific signal. So it would be nice to just set the flag if thread is
not waiting for the signal that was set.
Simplified signal setting as there is just one signal used for this purpose.
- No more pointers from kernel space to user space
    + osEvent are now read with to user space by using a syscall instead of a pointer
    + This change is a one step further to a virtual memory and protected mode
- Started developing semaphores
Moved signal syscall handler under ksignal module.
Cleaning up
Cleaning up
Fixed build errors.

Signed-off-by: Olli Vanhoja <olli.vanhoja@ninjaware.fi>