tmsUtils: fix broken UT test_convertStringToWallTime_n

Default value returned by convertStringToWallTime changed from 0
to 21600.
Undocumented change ?
tmsUtils: fix unit tests

Another undocumented behaviour change, when the wallTime is "",
we return a default value instead of an exception.
JsonObject: bugfix to getStringProperty with non-null terminated C string
JsonObject: minor fixes to deserialize

ensure that param_count >= 0
style fix
unit test: fix incorrect use of boost::shared_ptr

DIET_client_mock_unit_tests/my_test_serial_n
boost::shared_ptr::get allows to retrive a raw pointer but nothing
guarantees that it will remain usable during the whole scope of your test
You should retrieve the smart pointer and then use get when you need to pass
a raw pointer to *legacy* methods.
unit test: bugfix in DIET_client_mock_unit_tests/my_test_deser_n

param_count is an int and we fed jansson a string so it fails, period.
unit test: add a test case to DIET_client_mock_unit_tests
unit test: fix AnnuaryTests that were broken by design
Add sleep in loop to try getting new connexion