The arrow soc now has a memory used to hold if the first step has be triggered.

nb:  unexpected failures 175-> 162

Also name step function consistent and uniquely

nb:  unexpected failures 187->175

nb:  unexpected failures 195->187

Also start to add support for the other iterators, but it does not work yet.

nb: 20 more tests passes.

Always use Soc2cPredef.gen_assign to generate var assignments.

Also, use affection for assigning structures.

nb: 21 more tests passes.

Also do not crash if the soc contains reference to extern types.

- Generate code for most predef operators.
- Generate a loop.c file (in a similar manner as ec2c -loop does)