SGSN TTCN3 update

Hi,

I've pushed my SGSN Branch "attach fsm" where I reworked the Attach Request into an FSM together with a TTCN branch (replacing unit tests) to gerrit.

When both branches applied upstream, we're up to 42 tests. However these 4 test cases are still open:

pass->FAIL SGSN_Tests.TC_attach_pdp_act_deact_mt_t3395_expire => TEID wrong. Cleaning up the internal SGSN seems to fail. xfail SGSN_Tests.TC_attach_gsup_lu_timeout => HLR interaction xfail SGSN_Tests.TC_attach_gsup_lu_reject => HLR interaction xfail SGSN_Tests.TC_attach_second_attempt => HLR interaction

Best, lynxis