nlp address parser doesn't recognize highways

[slinkp]

For example:

>>> parse_addresses('hello, 2901 I-70 Drive NW, near my house')
[('2901 I', '')]

See also #264, #128, #291

[slinkp]

Ticket imported from Trac:
http://developer.openblockproject.org/ticket/292
Reported by: slinkp