log in/log out rewrite

Delete network object after logging out. related to #262
Support for multiple log in. related to #263 
Activate the tab if we already have one open and catch tab is closed #328 
Close a tab if user denies access #475 

I'll follow up with cl fixing storage state.
I think you can initialize the tabId_ above the constructor to remove this line, like:
```private tabId_ :number = -1;```