Adding blank element to server dropdown

This is so that if a server being used in a job gets deleted, the job wont
point to the first server in the list.  Could be dangerous if a VM in the
deleted server has the same name as one in the first server OR if someone
just makes a mistake and forgets to save a server.
Adding project logs for caught exceptions
Add handling for no servers in global config
variable expansion in server checks in build steps

ensure the server exists in the global config.  It's possible a server was
deleted but the job config was not updated and still holds the server
data.  It's also possible the server objects in the global config will
change while keeping the same name.  This check will prevent and
unexpected, and possibly dangerous operations.