update android cloud storage sdk version to v2.1.19
update iOS KiiCloudSDK.framework to v2.1.15
Merge pull request #1 from sbin/sdk-update

update android/iOS sdk to latest one
Update diagram
Fix API level.
Merge pull request #4 from KiiPlatform/app-imprv

Android tutorial app imprv
Merge remote-tracking branch 'upstream/master' into app-imprv-iOS

Conflicts:
	iOSSDKTutorialApp/KiiTutorialApp.xcodeproj/project.pbxproj