Refactor NSQLookupd to be importable

Refactor NSQLookupd to be importable

Fix formatting, make changes from comments on PR WRT exporting of variables

Rename imports package to nsqlookupd, move nsqlookupd/main.go to apps/nsqlookupd/nsqlookupd.go.

Attempt to fix TravisCI build of nsqlookupd

Change some testing variables back to private

Fixes after rebase

Make TcpAddr and HttpAddr unexported again, remove nsqld prefix from app
Merge pull request #292 from dinedal/master

nsqlookupd: refactor daemon to be importable
nsqadmin: fix prefixed HTTP handlers
nsqadmin: fix missing flag in flagSet
util: add paused to TopicStats
nsqd: add ability to pause a topic
nsqadmin: add ability to pause topic