Several bugs, did not work out of the box with wget 1.12-5

I noticed the following design flaws:
– if critical/warning thresholds are omitted, Python gives error “UnboundLocalError: local variable ‘warn’ referenced before assignment” instead of a proper command usage help
– Python 2.6.6 “DeprecationWarning: os.popen4 is deprecated. Use the subprocess module.”
– Parsing wget output is prone to errors, it only splits output line based on spaces and picks up

elems = lines[-2].split(” “)
size = elems[1]
num = elems[4]

Unfortunately at least for wget 1.12-5 on CentOS6.6 the structure of wget output did not match this assumption. I had to change it to
size = elems[3]
num = elems[1]

After this fix the plugin did seem to work.