802.1x broken for wired interfaces

[Tablet Mode]

802.1x authentication does not work properly for wired interfaces because the validation code is not called. This means that if the authentication is not done fast enough, wicd will continue setting an IP address etc. while not yet authenticated on the network yet, which will result in e.g. a wrong IP address.

I attached a patch which moves the auth validation to the BaseInterface class so it's available for both wireless and wired interfaces and adds the validation part for wired interfaces. Also it adds the optional CA cert setting to the wired_8021x template.
The patch was written for version 1.7.3 but it applies cleanly on 1.7.4 (tested on Gentoo).