ETISS Writer: Loops support is entirely broken

[PhilippvK]

There are several issues with the generation of loops in the ETISS Backend:

• Generated while and do ... while statements do not have curly braces. If coverage is enabled the only line in the loop body will be like cp.code() += "etiss_coverage_count(1, 5154);\n"; leading to unexpected behaior
  Solution: easy fix possible by adding missing {, }
• break statements are always considered static, even if their execution actually depends on a non-static if statement
  Solution: Fix would be to either declare a breaks/continues as non-static or keep track if the staticness of all Contionals...
• Loops are classified as static even if they may conditionally exit early via a break or continue statements
  Solution: Needs to analyze loop body in addition to loop condition
• parser splits up For loops in multiple statements (count_var delarator (+ count_var initializer) + actual Loop statement) which means that a non-static Loops will still have a statically-generated count_var (e.g. i) which of course breaks the simulation
  Solution: More difficult to handle as the behav.Loop does not know about his predecessor when is is being visited. We would either need to move the initialization statements into the behav.Loop class (self.init_exprs) or have to detect this one-layer earlier

The easiert workaround is of course to disable static loops entirely, but this is not a long-term solution...