* 1. add quantification_fold parameter. 2. support quantification test in run.py.

* implement n-fold quantification

* 1.add density_prior_box for gpu.
2.add flatten2 for gpu.
3.add concat 4 inputs size for gpu.
4.fix pool.
5.fix transpose2
test=develop

* 1.fix GetGPUTime
test=develop

* Catch mobile exceptions test=develop

* code style format test=develop

close #1791

1.update CPUContext to probe CPU info 2.improve the performance of SlidingwindowConv3x3s1 and SlidingwindowConv3x3s2 (#1655)

modify pridecttime judge