Not delaying auto increment columns by default any more.

It is still possible to do it by adding 'delayAutoIncrement' to the strategy.
Also adding unit tests for this method, they are needed.

@enisoc @aaijazi 

(Note I am adding the flag to the worker unit test so it keeps the same data, to not mess with Ammar's on-going changes).
My understanding is that usual Go style for test failures is of the format: "got: x, want: y" i.e., actual first, then expected. The rest of your errors follow that style, just not this one. It would be nice if this was consistent.