Added control if port string contains "\\\\.\\" on  Windows in functions AddtoPortsLists and RemoveFromPortsList
Call function AddtoPortsLists in if(found) and if (os==Windows) for Leonardo board.
Implemented new function unixExecAvrdude.
Added function unixExecAvrdude which makes a duplicate of the current process (fork) and replaces the entire new process with avrdude (exec). Added filesize function to use it in unixExecAvrdude so that we check if output file's size changes before kill avrdude process in case of hanging.