Fixes to use with WC

Addresses the following:

1) Introduces sidebar_login_widget_error_class filter which is used to style errors.
Defaults to sidebar_login_error, but can be filtered to use woocommerce-error

2) Honors SCRIPT_DEBUG define to select between .min.js and .js for debugging

3) Fixes SSL bug - 
I believe your check for FORCE_SSL_LOGIN to 'skip' Ajax is wrong. You should be checking force_ssl_login, not whether the URL is prefixed with https://
A site can set force_ssl_admin but not force_ssl_login, which is what I have done to get ajax on the login widget. 

4) My editor complained about your copyright symbol not being UTF8 and I think it changed it - so double check that.

5) I did not regen the .min.js