A bunch of updates

Thanks for the work on redisgosearch. I updated the package with the following features and one breaking change (which I believe is for the better).

New features:
1) README file based on your original post
2) Comments for all exported methods and types, so godoc.org can pick them up
3) Supports custom text segmentation functions
4) Test suite has less dependencies
5) Conforms to golint

Breaking change:
Creating a new client returns an err if it couldn't connect. That's more idiomatic than panic'ing.