timob-14311: need to set opacity after backgroundColor is changed.
TIMOB-12222: Remove tiapp.xml from build/android/bin/assets for all builds.
timob-14311: add check for API level.
timob-14311: set opacity after background is changed.
Merge pull request #4421 from ayeung/timob-12222

TIMOB-12222: Remove tiapp.xml from build/android/bin/assets for all builds
Merge pull request #4418 from pingwang2011/timob-14311

timob-14311: Android: View: opacity does not work when backgroundColor is changed