controlpanel: rename GetUser() to FindUser()

Avoids conflict with CModule::GetUser()
Modules: use public API

Avoid accessing protected member variables directly, so
there's a chance of cleaning up the module API later.
Write disabled status to chan config
Fix #597: make autoop save added masks
fix #690: make autoattach a network module
Merge pull request #701 from jpnurmi/modules-pubapi

Modules: use public API
Merge pull request #702 from jpnurmi/disabledchan

Write disabled status to chan config
Merge pull request #706 from jpnurmi/autoattach

fix #690: make autoattach a network module
Merge pull request #703 from jpnurmi/autoop

Fix #597: make autoop save added masks
CChan: keep track of the channel key

There are situations when a module simply cannot know the channel key.
For instance, when the module gets loaded when user is already on a key
protected channel. It's better to make CChan keep track of the key.
Refactor chansaver (#674)

CChan now keeps more reliably track of the channel key.