Changes

pySim-shell: add new commandline option "--pure"

by default pySim-shell does all kinds of probing and file selection
on startup. This is to determine the card type and to find a suitable
card profile. However, in case the card is non yet provisioned this
probing may cause a error messages and even might upset the cards
internal state. So let's have a commandline option thrugh which we
can instruct pySim-shell to skip any initialization and to give us
a prompt immediately, so that we can enter custom APDUs

Related: OS#6367
Change-Id: I1d8a57de201fe7ad7cbcbc6f72969ea8521e821d