Added support for an optional HTTP proxy when accessing ISPDB URLs.

Thus file 'autoconfig.properties' is enhanced by the following options:
- com.openexchange.mail.autoconfig.ispdb.proxy
- com.openexchange.mail.autoconfig.ispdb.proxy.login
- com.openexchange.mail.autoconfig.ispdb.proxy.passw ord



The property com.openexchange.mail.autoconfig.ispdb.proxy is supposed to provide the proxy host to use in notation:

<proxy-protocol> + :// + <proxy-host> + : + <proxy-port>
(With http:// as fall-back protocol)

E.g. 67.177.104.230:58720 (using HTTP protocol) or https://78.0.25.45:8345 (using HTTPS protocol)

Default is empty (no proxy used).



The property com.openexchange.mail.autoconfig.ispdb.proxy.login is supposed to provide the optional user-name/login in case the specified proxy host requires authentication.

Default is empty (no authentication)



The property com.openexchange.mail.autoconfig.ispdb.proxy.passw ord is supposed to provide the optional password in case the specified proxy host requires authentication.

Default is empty (no authentication)