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
modify log info(remove unuseful log and add some new logs)
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
Install the import library via the EXTRA_LIB mechanism on mingw as well

Prior to 3f69873c99, there already was a mechanism for installing
the import library, used for the MSVC builds. Use that for mingw
as well, instead of adding more hardcoded rules.
Set the right SHAREDLIBSUFFIXVER for msvc
Honor the silent build flag when adding the shared library symlink
Fix the dependencies of the install-shared target

Previously calling "make install" failed unless the target
actually already was built, for platforms where the shared
libraries are versioned.
Simplify setting the shlib flags for msvc
Actually install the versioned shared library file as well