* fix building ios tiny publish lib error

* support setting cluster and threads in MobileConfig

* fix build error, test=develop

* fix building server publish error, test=develop

add model_run_test_image
    add range_max_quant op
    add flatten op
    add flatten2 op
fix:
    fix density_prior_box density_size type from float to int
    fix prior_box and density_prior_box some check for get_attr
test=develop