MVP feature :: custom ports list builder about netbang HOT 3 CLOSED

parsePortsCdl() parses the comma-delimited string passed in by the user, using
the --ports flag. Since the user can specify either numbers or port list names,
the func must detect item type 1st, then perform validation. In the case of
port numbers, since we bring everything as string data, there is some fun
converting runes. Returns ports as []uint16, any named port lists as []string.

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TO DO:

1. Plumb ports to final []uint16 port array to pass to scan() functions
2. Create some sort of "named lists" lookup to be used with --ports flag
   2.5) Nice-to-have: create a way for users to edit/create new named lists from a config file

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1. and 2) done. Nice-to-have would still be nice to have, but this can be called "done" :) See commit fffbc51

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