Master TCP/TLS client fail-over support

[jadamcrain]

Currently, the host parameter specified when creating a TCPClient or TLSClient can either be an IPv4 address or a DNS name that gets resolved.

We need to extend this string value to allow for a list of IP addresses to attempt to connect to in the specified order, e.g.:

"<ip1>;<ip2>; ... ;<ipN>"

The advantage of doing things this way is that it won't break the current API.