Creates a TmpConfig helper

To help test the output from BBConfig which varies alot based on the
contents of a config file, this helper creates a temporary directory and
config file using the desired contents.

Has a simple accessor to get the dir back to pass in as the :directory
option of BBConfig.new and a #close method
Tests BBConfig#client_name with options support

Added the means to pass in client_name and account to BBConfig as
options.