WiMax profile exit code logic

-Updated WiMax profiles script on both Powershell and AutoIt side to
include some exit logic. Exiting with code 1 is generic failure, code 0
is success. $LASTEXITCODE was either null or inaccessible no matter how
I used it; error level is not passed up from AutoIt script correctly.
Instead, I write error code to a file from AutoIt script, read from
Powershell script, and delete the file afterwards.