libomptarget

micro steps in omptarget.

1. map analysis, enter data region. generate H2D and D2H pair lists, first-private array list,
2. resolve dependency in. wait events
3. transfer H2D
4. launch kernel
5. transfer D2H
6. create dependency out. record events.
7. exit data region. decrease reference counting, delete first-private array items.

*) target: 1, q_start, 2-6, q_stop, 7 *) target data:. 1, q_start, 2-3, q_stop, host region, q_start, 5, 6, q_stop, 7 *) target enter data: 1, q_start, 2-3, 6 q_stop *) target exit data: 1, q_start, 3, 5-6, q_stop, 7 *) target update 1, q_start, 2-3, 5-6, q_stop, 7