Bugfix in Horner's scheme

Closes #78.

Author: Arda Aytekin

src/Polynomials.jl

@@ -368,7 +368,7 @@ function polyval{T,S}(p::Poly{T}, x::S)
     if lenp == 0
         return zero(R) * x
     else
-        y = convert(R, p[end]) + zero(T)*x
+        y = convert(R, p[end])
         for i = (endof(p)-1):-1:0
             y = p[i] + x*y
         end

test/runtests.jl

@@ -250,3 +250,11 @@ r = Poly([1.0, 2, 3])
 p = poly([1,2,3])
 q = poly([1,2,3])
 @test hash(p) == hash(q)
+
+## Check for Inf/NaN operations
+p1 = Poly([Inf, Inf])
+p2 = Poly([0, Inf])
+@test p1(Inf) == Inf
+@test isnan(p1(-Inf))
+@test isnan(p1(0))
+@test p2(-Inf) == -Inf