Use GetDefaultParams instead of memset to initialize SEncParamExt in the console test app

Most of the default parameters still are overwritten with hardcoded
values in FillSpecificParameters though, but this makes sure that
defaults are applied for any new fields at least.
fix BGD under screen and remove a build warning in ME
Use += for all submodules INCLUDE variables

This makes it easier for platform specific makefiles to add
things to some of them. (build/platform-android.mk already does this
for a few submodules, e.g. GTEST_INCLUDES and CODEC_UNITTEST_INCLUDES
already use +=.)
Remove leftover include directories

codec/common no longer contains headers, they're all in
codec/common/inc now.
Build the android cpu-features.o file in codec/common/src

Up until now it was built in codec/common (where all other common
source files were built, until they were split up into
inc/src/x86/arm/arm64).
add encoder interface UT for IDR request
Ignore failures in cleaning android projects

If the android test projects hasn't been built yet, the "make clean"
command will stop at "ant clean" (which fails since build.xml doesn't
exist yet). If this happens, one still would want to run the "make
clean" command to the end, cleaning up any possible intermediate object
files (e.g. from a build for a different platform).
Regenerate test/common/targets.mk via the mktargets.sh script as well
Remove an unused function in mktargets.py
Merge pull request #1067 from lyao2/interface_ut_commit

encoder interface UT for temporal layer setting change
Merge pull request #1069 from mstorsjo/generate-targets

Regenerate test/common/targets.mk via the mktargets.sh script as well
Merge pull request #1065 from mstorsjo/remove-old-includes

Remove leftover include directories
add bgd fix to camera route as well to avoid visible artifact when using fake content in video
fix a typo issue in ParamValidation
Merge pull request #1062 from sijchen/scc_md_bgd1

fix BGD under screen and remove a build warning in ME
Merge pull request #1071 from ganyangbbl/typo_bug

fix a typo issue in ParamValidation
Only force iLoopFilterDisableIdc to 2 if multithreading has been enabled

Previously these lines were within an #ifdef MT_ENABLED block,
but now that threading is enabled by default, we should probably
only do it if threading has been requested.
Merge pull request #1068 from mstorsjo/android-clean

Ignore failures in cleaning android projects
Merge pull request #1066 from mstorsjo/android-cpufeatures-dir

Build the android cpu-features.o file in codec/common/src
Merge pull request #1070 from mstorsjo/remove-unused-function

Remove an unused function in mktargets.py