Allow 1 element array to behave as single element of appropriate type

[ggggggggg]

The following works in MATLAB, and it would be nice to have the same functionality in julia. It seems easy to do by defining the appropriate cases for convert.

Julia Studo 0.3.2

julia> a = [1]
1-element Int64 Array:
 1
julia> b = [1:4]
julia> b[2]=a
no method convert(Type{Int64},Array{Int64,1})

MATLAB

>> a = [1];
>> b = [1:4];
>> b(2) = a

b =

     1     1     3     4

[JeffBezanson]

Embedding scalars as arrays is discussed in #3262.