Add bretep to authors
document pkg.purge on Windows
cmdmod: fix W1401 (Anomalous backslash in string) problems
utils.parsers: fix pylint W1401 (Anomalous backslash in string) problems
tty => teletype, to avoid shadowing
fix undefined var in modules.pecl
version => nver, to avoid shadowing version() func
more detailed feedback if the ssh.set_known_host failed to append to known hosts file

Commands should always tell the reason on why they have failed.
Changing from printf style to string formatting