runtests (in 0.7) fails with Test.detect_ambiguities(FixedPointNumbers, Base, Core)

[lobingera]

i merged manually #100 into master and ran. Precompile works, but Pkg.test fails (obviously with Base.Test and Test as stdlib), but also

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julia> using FixedPointNumbers

julia> using Test

julia> Test.detect_ambiguities(FixedPointNumbers, Base, Core)
8-element Array{Tuple{Method,Method},1}:
 ((::Type{Fixed{T,f}})(x) where {T, f} in FixedPointNumbers at /home/lobi/.julia/v0.7/FixedPointNumbers/src/fixed.jl:8, (::Type{T})(z::Complex) where T<:Real in Base at complex.jl:37)                        
 ((::Type{Normed{T,f}})(x) where {T, f} in FixedPointNumbers at /home/lobi/.julia/v0.7/FixedPointNumbers/src/normed.jl:8, (::Type{T})(x::T) where T<:Number in Core at boot.jl:686)                            
 ((::Type{Fixed{T,f}})(x) where {T, f} in FixedPointNumbers at /home/lobi/.julia/v0.7/FixedPointNumbers/src/fixed.jl:8, (::Type{T})(x::Char) where T<:Number in Core at boot.jl:684)                           
 ((::Type{Normed{T,f}})(x) where {T, f} in FixedPointNumbers at /home/lobi/.julia/v0.7/FixedPointNumbers/src/normed.jl:8, (::Type{T})(z::Complex) where T<:Real in Base at complex.jl:37)                      
 ((::Type{Normed{T,f}})(x) where {T, f} in FixedPointNumbers at /home/lobi/.julia/v0.7/FixedPointNumbers/src/normed.jl:8, (::Type{T})(x::Base.TwicePrecision) where T<:Number in Base at twiceprecision.jl:243)
 ((::Type{Normed{T,f}})(x) where {T, f} in FixedPointNumbers at /home/lobi/.julia/v0.7/FixedPointNumbers/src/normed.jl:8, (::Type{T})(x::Char) where T<:Number in Core at boot.jl:684)                         
 ((::Type{Fixed{T,f}})(x) where {T, f} in FixedPointNumbers at /home/lobi/.julia/v0.7/FixedPointNumbers/src/fixed.jl:8, (::Type{T})(x::Base.TwicePrecision) where T<:Number in Base at twiceprecision.jl:243)  
 ((::Type{Fixed{T,f}})(x) where {T, f} in FixedPointNumbers at /home/lobi/.julia/v0.7/FixedPointNumbers/src/fixed.jl:8, (::Type{T})(x::T) where T<:Number in Core at boot.jl:686)