Implement unique prefix matching for --TYPE command line params.

[Gary R. Van Sickle]

For feature parity with at least ag and ack, which both support --py while we need the full --python.

[Gary R. Van Sickle]

Note on support for --noTYPE:

• ag doesn't support that syntax.
• ack does support this, with the expected ambiguity detection behavior, i.e.:

$ ack --noc '\bimport\b' ../
Option noc is ambiguous (nocc, nocfmx, noclojure, nocmake, nocoffeescript, nocolor, nocolour, nocolumn, nocpp, nocsharp, nocss)
ack: Invalid option on command line

Following ack behavior on this one.