Adding configurable tld

Done by adding a tld value to config, and reading it via env passed in to resolver_config. Thus the tld value will only effect how the resolver is setup on OSX for guest resolution.
Adding docs for landrush.config.tld usage
Update config.landrush.tld wording

Wording was a little off with unnecessary parenthesis.
Merge pull request #26 from highb/master

Adding configurable tld