Various SSL, auth, and UI changes

Changed encryption types, removed "SSL/TLS (untrusted)" option.
Existing client connections that use "SSL/TLS (untrusted)" will be
converted to "SSL/TLS" by the SQLite database upgrade.
Fixed a couple of client crashes that occurred when interrupting
a connection to the VM before reaching the proxying state.
Added field to IAuthType to prevent automatically re-authenticating
with an auth type that doesn't require input.
Made various UI changes to AppRTC activity, including a progress
dialog so the connection doesn't appear to be erroring out.
Deleted unused "client_side" layout file.