Add handle function to Thread type
Add handle function to Thread type

Exposes SysThread type and introduces the function "handle" to return Thread.sys.
singularperturbation/Nim,jfhg/Nim,haiodo/Nim,russpowers/Nim,russpowers/Nim,jfhg/Nim,mbaulch/Nim,russpowers/Nim,singularperturbation/Nim,singularperturbation/Nim,singularperturbation/Nim,dom96/Nim,haiodo/Nim,dom96/Nim,haiodo/Nim,singularperturbation/Nim,jfhg/Nim,dom96/Nim,russpowers/Nim,russpowers/Nim,mbaulch/Nim,singularperturbation/Nim,jfhg/Nim,mbaulch/Nim,dom96/Nim,haiodo/Nim,haiodo/Nim,jfhg/Nim,tulayang/Nim,tulayang/Nim,mbaulch/Nim,haiodo/Nim,mbaulch/Nim,mbaulch/Nim,jfhg/Nim,tulayang/Nim,dom96/Nim,tulayang/Nim,russpowers/Nim,singularperturbation/Nim,jfhg/Nim,dom96/Nim,tulayang/Nim,mbaulch/Nim,dom96/Nim,tulayang/Nim,russpowers/Nim,haiodo/Nim