Fix test errors (#200)

Some tests failed on 32bit systems, seems tolerances were too strict (-0.108... in the test and absolute tolerance was 0.1).

Author: devmotion

test/serialization.jl

@@ -51,7 +51,7 @@
             for samples in (samples1, samples2)
                 @test samples isa Vector{Float64}
                 @test length(samples) == n
-                @test mean(samples) ≈ 0 atol=0.1
+                @test mean(samples) ≈ 0 atol=0.15
                 @test std(samples) ≈ 1 atol=0.1
             end
         end