Currently, the TCP_STACK_SIZE is `KERNEL_CONF_STACKSIZE_DEFAULT`.
However, since printf statements are used in the tcp relevant code,
this stack size is too small (esp. for MSBA2).
This enum is also used to set the tcp flags within a tcp header.
With the current values in this enum, wireshark is not able to
recognize the tcp segments as their actual tcp type,
and thus odd messages in wireshark appear.
destiny: reusing tcp flags for combinations
