typos in readme

Author: Nick Eubank

README.md

@@ -6,7 +6,6 @@ Tools for interoperability between DataFrame objects and LightGraphs and MetaGra
 
 ```
 julia> using DataFrames
-julia> using MetaGraphs
 julia> using GraphDataFrameBridge
 
 julia> df = DataFrame(Dict("start" => ["a", "b", "a", "d"],
@@ -15,20 +14,20 @@ julia> df = DataFrame(Dict("start" => ["a", "b", "a", "d"],
                            "extras" => 5:8))
 
 # Simple undirected MetaGraph
-julia> mg = MetaGraph(df, :start, :finish, MetaGraph)
+julia> mg = MetaGraph(df, :start, :finish)
 {5, 4} undirected Int64 metagraph with Float64 weights defined by :weight (default weight 1.0)
 
 julia> props(mg, 1)
 Dict Symbol → Any with 1 entries
   :name → "a"
 
 # Simple directed MetaDiGraph
-julia> mdg = MetaDiGraph(df, :start, :finish, MetaDiGraph)
+julia> mdg = MetaDiGraph(df, :start, :finish)
 {5, 4} directed Int64 metagraph with Float64 weights defined by :weight (default weight 1.0)
 
 # MetaGraph with `weight` attribute set and
 # `:extras` values stored as attributes.
-julia> mgw = MetaGraph(df, :start, :finish, MetaGraph,
+julia> mgw = MetaGraph(df, :start, :finish,
                                       weight=:weights,
                                       edge_attributes=:extras)
 {5, 4} undirected Int64 metagraph with Float64 weights defined by :weight (default weight 1.0)