Added doc folder and a document template

The doc/ folder will contain all the documentation of the project.
The "Evernote-bq App Specification" will contain the whole info about
the project such as: problem to resolve, solution proposed, architecture
and so on.
Evernote example created

Evernote example is an App based on the example provided by Evernote Dev
Team to teach developers how to use the official API.
+ Added authentication functionality using oAuth system provided by Evernote SDK.
+ Added activity_login.xml and LoginActivity to allow users to sign into the app
+ Added home.xml and HomeActivity where a note list will be shown.
+ Added Logout action to the Action Bar menu.
+ Modified AndroidManifest.xml with the definition of a new permission (INTERNET) and new activities.
Merge branch 'evernote-sample' of https://github.com/MyGonBa/evernote-bq into develop
Note list and note details views added

+ Added functionality to show all user notes on HOME view.
+ Added functionality to show note details from a note selected (tap) by
the user.
+ Added BQ logo for Login view.