add UT for sim-SVC switch
reformat cpp files for next release
fix bug in set option return value
reformat cpp files for unit tests
Add casts to avoid warnings about comparison between signed and unsigned
Only use pthread_setname_np on Android >= 9 (2.3)

Older versions of Android don't have this function.
Merge pull request #1441 from mstorsjo/avoid-warnings

Add casts to avoid warnings about comparison between signed and unsigned
Merge pull request #1442 from mstorsjo/android-pthread-setname

Only use pthread_setname_np on Android >= 9 (2.3)
Merge pull request #1439 from sijchen/for_format

[Reformat] format cpp files for next release
Merge pull request #1440 from shihuade/APIUTV1.4

fix bug in set option return value
Merge pull request #1443 from dongzha/AddUTSwitch

add UT for sim-SVC layer switch
Merge remote-tracking branch 'upstream/master' into travis.osx