Initial version of the mailer

can send generic message using string for body, subject and recipient
[Issue #189] Added documentation to the mailer methods
[Issue #189] Added test framework
Merge branch 'master' into C4_m0hamed_C5F1_send_mail
[Issue #189] Added tests
Added Guardfile and rspec to .gitignore
Merge branch 'C4_m0hamed_C5F1_send_mail' into rolling_master