Fix issues with linux and OSX permissions and update linux64 stlink upload script (issues 1 and 2)

linux64/stlink_upload

@@ -1,4 +1,8 @@
 #!/bin/bash
+$(dirname $0)/stlink/st-flash write "$4" 0x8000000
+exit 0
+
+## Remove the lines 2 and 3 (above) if you want this script to wait until the Serial device has been enumerated and loaded before the script exits
 
 # Check for leaf device.
 function leaf_status()