test/rilmodem: add new SIM functional tests

This commit adds Python unittest-based functional test scripts
used to test the SIM functionality of an instance of ofono using
the rilmodem/mtkmodem drivers.
test-sims-online: document cmd-line args
test/rilmodem: add test-sim-removal
Merge pull request #136 from tonyespy/first-sim-tests

Tested in mako and krillin, vivid.
test/rilmodem/sim: updates to testsimutil

Add arg parsing support for enable/disable
PIN locking tests.  Also, in validate_sim_props,
only check 'PinRequired', not 'LockedPins'.
test/rilmodem/sim: update test-sim* scripts

Update test-sim-* scripts based on changes to
simtestutil module for disable/enable PIN
lock tests.
test/rilmodem/sim: disable/enable SIM lock tests

Add tests for enabling/disabling SIM PIN locking.
test/rilmodem/sim: fix test-sim-enable-pin-lock
test/rilmodem/sim: add change-pin test
Merge pull request #137 from tonyespy/sim-locking-tests

Sim locking tests