Safely build 64-bit binaries along with some modernization.

[muojp]

This pull-req contains several changes to come over 32-bit/64-bit situation of new Google Play's policy.

Changes made:

• Remove mips from APP_ABI because recent NDK lacks support for them
  • Specifying all is reasonable especially for recent NDKs because at least NDK r18 complains armeabi is deprecated.
• Upgrade Gradle and corresponding build scripts for better app integration
  • Also upgrade versionBuildTool to align build tools with Android gradle plugin
• Specify https instead of http for URI schema of libcommon to avoid possible DNS poisoning attack

Note: According to recent Google's annoucements, APK size issue addressed here is meant to be mitigated via Android App Bundle.

Note: You will see Android NDK: android-14 is unsupported. Using minimum supported version android-16. warning when built with NDK r18 but you can easilly fix this by specifying older NDKs on local.properties file if you really need to keep support for Android 4.0.x. I assume most developers (targetting android-16+) can harmlessly ignore this warning because their app themselves will be compiled with minSdkVersion 16 or later.

[muojp]

I'm great to see this happen! Now I'll rebase changes upon the latest master branch.

[muojp]

Now we have only 1 line to change :+1:

[janoonaj]

Merge this branch is needed because UVCamera library is compiled on 32-bit, causing couldn't find "libjpeg-turbo1500.so" exception if there are 64-bit libraries on the project

APP_ABI := all does not compile for me, use APP_ABI := armeabi armeabi-v7a arm64-v8a instead

[deebashd]

Also uncomment #NDK_TOOLCHAIN_VERSION := 4.9 line in Application.mk before generating build. Otherwise the library won't work as expected.