Move the show functionality into summary

`summary` gets called by `show`. This approach improves modularity.

Author: timholy

src/core.jl

@@ -343,28 +343,21 @@ dropax(ax) = ()
 # A simple display method to include axis information. It might be nice to
 # eventually display the axis labels alongside the data array, but that is
 # much more difficult.
-if VERSION < v"0.5.0-dev"
-    function Base.writemime{T,N}(io::IO, m::MIME"text/plain", A::AxisArray{T,N})
-        println(io, "$N-dimensional AxisArray{$T,$N,...} with axes:")
-        for (name, val) in zip(axisnames(A), axisvalues(A))
-            print(io, "    :$name, ")
-            Base.showlimited(io, val)
-            println(io)
-        end
-        print(io, "And data, a ")
-        writemime(io, m, A.data)
-    end
-else
-    function Base.show{T,N}(io::IO, m::MIME"text/plain", A::AxisArray{T,N})
-        println(io, "$N-dimensional AxisArray{$T,$N,...} with axes:")
-        for (name, val) in zip(axisnames(A), axisvalues(A))
-            print(io, "    :$name, ")
-            show(IOContext(io, :limit=>true), val)
-            println(io)
-        end
-        print(io, "And data, a ")
-        show(io, m, A.data)
+function summaryio(io::IO, A::AxisArray)
+    _summary(io, A)
+    for (name, val) in zip(axisnames(A), axisvalues(A))
+        print(io, "    :$name, ")
+        show(IOContext(io, :limit=>true), val)
+        println(io)
     end
+    print(io, "And data, a ", summary(A.data))
+end
+_summary{T,N}(io, A::AxisArray{T,N}) = println(io, "$N-dimensional AxisArray{$T,$N,...} with axes:")
+
+function Base.summary(A::AxisArray)
+    io = IOBuffer()
+    summaryio(io, A)
+    String(io)
 end
 
 # Custom methods specific to AxisArrays