Update Csocket to e818c7b0d31b0ed71c74f9d0035b58efd73f3988

This adds support for character encodings, and decreases CPU usage in
some cases
Add support for character encodings

Previous commit added support of it to Csocket.
When encoding is specified, core will convert incoming messages to UTF-8,
and outgoing messages from UTF-8.
When no encoding is specified, it will do nothing to bytes, like before.
This is to be changed somewhere in future, to have UTF-8 on wire by
default too.
When encoding's name starts with *, incoming messages will be treated as
UTF-8, if it is already correct UTF-8. Otherwise, it's converted.

Fix #151
Fix #366
Drop old charset module

It didn't work well with webadmin
Add charset to version info
Add libicu-dev to travis config
Fix alias mod to compile with old compilers
Don't ask if user wants to create znc.pem or not

Sure they want!
Don't reread list of TZs every time
Support encodings in *controlpanel