add feature: verify that sim has correctly acknowledged PIN code
check if initial sim card response is OK
add debug_mode option to Sim
refactoring: introduce AtInterface to allow easier AT command mocking for tests
Merge branch 'master' into next_gen
minor
reintroduce Sim.send_raw_at_command
introduce Phonebook
add fuzzy_search_by_number to phonebook
fix bug: do not load empty phonebook entries
release version 0.1.0
update rdoc
update readme
release version 0.1.1