JC-1993: Add ability to Sign Up from Login forms

New 'Sign Up Right Now' link was added into 'Sign In'
modal window as wel as login page.

* New sign_up_right_now link was added into sign_in modal and /login page.
Merge pull request #26 from jtalks-org/JC-1993.sign_up_link_on_sign_in_dialog

JC-1993: Ability to sign up from /login page and login modal windows was added.