Add support for KDE keyring

[pulb]

Mailnag currently only supports GNOME-Keyring for encrypted password storage. On non-GNOME desktops account passwords are strored in Mailnags config file.

Analogous to GnomeCredentialStore, the should be a be a class KDECredentialStore. The class is required to inherit from the CredentialStore base class and needs to implement the follwoing methods:

def set(self, key, secret)   
def get(self, key)  
def remove(self, key)

That's all. Contributions are highly appreciated.

[alekksander]

+1 is it doable? i know there is such plugin for pidgin, perhaps some of it's code is re-usable