renamed nil? to is_nil
Merge pull request #18 from aforward/f/nil_to_is_nil

renamed nil? to is_nil
Release v0.6.0
Bump to v0.6.1-dev
Updated documentation to include mandatory params
Merge pull request #19 from aforward/f/query_example_usage

Updated documentation to include mandatory params
Split Connection module into Protocol
Replace :gen_server => GenServer
Fix encoding `nil` values in arrays and composite types

Closes #20.