add iBitsVaryPercentage parameters to control bitrate
add dec status for freezing
remove a too-tight checking of bit rate
use iBitsVaryPercentage passed by the app instead of the macro
Merge pull request #1573 from sijchen/after_review1

[Encoder] remove a too-tight checking of bit rate
add SetOption(ENCODER_OPTION_SVC_ENCODE_PARAM_BASE,&base) for encoder
avoid using the same picture buff for prev pic and curr pic
Merge pull request #1575 from ruil2/set_param

add SetOption(ENCODER_OPTION_SVC_ENCODE_PARAM_BASE,&base) for encoder
Merge pull request #1574 from huili2/dec_stat_add_freeze

add dec status for freezing
Merge pull request #1568 from ruil2/cleanup

add iBitsVaryPercentage parameters to control bitrate
use existed assembly function in cabac encoder
Merge pull request #1567 from dongzha/FixMvCpBug

avoid using the same picture buff for prev pic and curr pic
Merge pull request #1578 from ruil2/rc

use existed assembly function in cabac encoder