fix a calculation of fAverageFrameRate
fix bug of parse error return for VCL data
Merge pull request #1522 from sijchen/after_review

[Encoder] fix a calculation of fAverageFrameRate
Merge pull request #1524 from huili2/parse_err_return_bug_fix

fix bug of parse error return for VCL data
Merge branch 'master' of https://github.com/cisco/openh264 into working0
complete most of the statistis calculation