README: use `-create` instead of `-applet`

[darconeous]

The README had incorrect instructions for the installation of the applet, using the argument -applet instead of -create.

@martinpaljak notes the difference between the two:

--create specifies the instance AID and that needs to be the NFC forum defined one. ... --applet, when used with --install selects a module from multi-applet package (or the module after a standalone --load).

This change simply changes the instances of -applet to -create to ensure that the installed applet is given the correct AID.

[darconeous]

Not sure what's up with Travis. This is just a README change.

[mattdibi]

Had issues installing the applet on my card. These instructions fixed the problem, thanks.

[EmperorArthur]

+1 to this please. I spent hours searching because I did not realize what was going on!