Enable/Disable captcha in mobile user form too
Merge pull request #20 from nemesisdesign/master

Finish captcha tweak
fixes spurious exceptions if a user submits a blank password
Gestpay payment gateway support draft
avoid to send 1 request per second to gestpay
fixes password recovery for mobile phone
fixes email password recovery
fixed issues with gestpay payment gateway
server2server gestpay fix
Gestpay payment gateway in <iframe> + minor improvments to payment process
Some fields in the registration form can be configured to be optional
added migration for optional user field "birth_date" + minor change to account_common.rb
More improvements on Gestpay verification method.

* improved code clarity
* improved usability
* gestpay error case should not cause the user to get stuck anymore

Needs testing and most probably a bit more work.
moved "clear_gestpay_url" in account_common.rb and renamed to "clear_gestpay_notes"
show credit card verification block if gestpay verification method is on but paypal is off
added possibility to specify a different currency for paypal
added gestpay link to mobile + added gestpay logo
show loading overlay after successful gestpay verification
renamed "credit_card" with "paypal" wherever it makes sense
minor changes