Add alternative search methods
    use WelsLog instead of fprintf to have a unified trace output
Merge pull request #604 from ruil2/vp_trace

    use WelsLog instead of fprintf to have a unified trace output
Merge pull request #602 from sijchen/fme_merge22

[Encoder ME] Add alternative search methods
Merge branch 'master' of https://github.com/cisco/openh264 into vp_update2
use function pointer in reference frame management