Added some comments to the code that handles SDK interaction.
Create README.txt
Readme instructions for the Build demo app
Delete README.txt
readme instructions for building and running the dmeo app.
Update README.md

Readme instructions for building and running the demo app for build.
Uploading the jar file of exchange SDK.
Merge branch 'exchange_share' of https://github.com/OfficeDev/Office-365-SDK-for-Android into exchange_share
Changed the jar file for "exchange_share_demo" branch.