fix in Range constructor

before the fix:

julia> (1:3:10) - 0.5
no method Range(Float64,Int64,Int64)
 in method_missing at base.jl:60
 in - at range.jl:130

after:

julia> (1:3:10) - 0.5
0.5:3.0:9.5

base/range.jl

@@ -16,8 +16,9 @@ type Range{T<:Real} <: Ranges{T}
         new(start, step, len)
     end
     Range(start::T, step::T, len::Integer) = Range(start, step, int(len))
+    Range(start::T, step, len::Integer) = Range(start, convert(T,step), int(len))
 end
-Range{T}(start::T, step::T, len::Integer) = Range{T}(start, step, len)
+Range{T}(start::T, step, len::Integer) = Range{T}(start, step, len)
 
 type Range1{T<:Real} <: Ranges{T}
     start::T