Registartion templates updated


**Functionalities implemented:**

1) Registration templates updated
 
   - For time being wherever possible, implemented {% trans %} template-tag and for remaining ones implemented {% blocktrans %} template-tag
   
   - Files modified:
   
     1) templates/registration/activate.html
     2) templates/registration/activation_complete.html
     3) templates/registration/activation_email.html
     4) templates/registration/login.html
     5) templates/registration/logout.html
     6) templates/registration/password_change_form.html
     7) templates/registration/password_reset_complete.html
     8) templates/registration/password_reset_done.html
     9) templates/registration/password_reset_email.html
     10) templates/registration/password_reset_form.html
     11) templates/registration/registration_closed.html
     12) templates/registration/registration_complete.html
     13) templates/registration/registration_form.html 
     14) templates/registration/activation_email.txt
     15) templates/registration/activation_email_subject.txt
     16) templates/registration/password_reset_email_subject.txt