Updte support library version
Update Sdk version
Use ActivityLifecycleCallbacks instead of calling on Activity#onCreate
Extract notification class
Check whether if activity if FragmentActivity
Rename method
Move package of SystemProfileBuilder
Enable to set report mail body
Update README.md
Reconstruct `SystemProfileBuilder` -> `SystemProfile`
Rename interfaces `initialize, destroy` -> `start, stop`
Validate filed of ReportMail
Move package of ActivityLifecycleCallbacks from library to sample
Change minSdkVersion `14` -> `8` in library
Merge pull request #4 from rejasupotaro/use_activity_lifecycle_callback

Change interfaces easier-to-use