Refactor:
Mail Class
MailClient Interface
MailClientMock Class
Main MailVoicetivity class + Three of its states.
Added Command and reponse strings to strings.xml
Voicetivity States 0, 1 and 2 mostly finished ( Waiting for the next states to complete them)
 Response and Command Strings added.
Merge pull request #4 from DaniMunin/master

master