Added icomoon font
Added PasswordTextField
LoginViewController and SignupViewController use new PasswordTextField. Closes #177
Update LoginHeader.png
Merge pull request #209 from toggl/kaanjin-iospasswordtextfield

New password text field with visibility toggle for Login and Signup views
Merge pull request #219 from toggl/taavirehemagi-loginheader

Update login header. Closes #216