Increases max buffer size for bufio.Scanner even more

Doubles max buffer size for bufio.Scanner

Output usage on unknown mode

Makes json output mode use an empty array for parameters instead of null

Adds extension format specifier (%e); tomnomnom#9

Adds apexes mode; updates install instructions etc

Adds keypairs option

Adds note to README about empty output; fixes tomnomnom#2

Import from hacks repo