Fixed null pointer exception that occurs on connection attempt made
from the server properties screen.
Issue a message when connection attempt fails.
More text string literals replaced by the respective resource
references.
Channels navigation fix.

The channel joining action has been generalized. For instance, it
fixes the situation when the user information was lost as a result of
switch to the parent channel.
Used singleLine attribute for the majority of input fields where it
seems to be appropriate.

This prevents occasional newline character that could be just harmful
in such fields, for instance, as server address.
Just a minor fix.
Merge pull request #18 from poretsky/proposals

Android app fix