cleanup: another cleanup session (data_exchange_main.c) Cleanup all kinds of stuff in one of the core functions. Made local data static, with 1 already existing exception (the dataIn data). For this, a trivial change is made in t7.c. In addition, not used code, and commented out code that seems highly obsolete is removed. Another tiny step in code that is better to maintain in the future. Signed-off-by: Jan Mulder <jlmulder@xs4all.nl>