add variant_length, repair send_reqest
change code to use add_variant
Create self_test_code for all functions
self_test_frame
remove error in fc.c / send_frame
Add test for frame
create all self_test expect error
remove merge errors
Tests for all
add send and recv errorcode
self_test_error
add error return in test_recv
Add and test error handling, errors get back until first level
change Comments
Merging is complete