unittests: add testcases for decode_select_response
A CardProfile class usually contains a static method decode_select_response. Unfortunately those methods have no unit-test coverage yet. Let's add unit tests for the decoders in CardProfileSIM and CardProfileUICC.
pySim/ts_51_011: rewrite comment for better understanding
The comment reads like that we were applying TS 102.221 here, but we only mean our internal decoding format. The spec that actually matters here is TS 51.011. Let's rephrase the comment so that this becomes more clear.
