isinteger(::Normed) incorrect

[cjdoris]

The code currently assumes that the denominator is 2^f, which is not the case for Normed. e.g.

julia> isinteger(Normed{UInt8,7}(1))
false

I believe you need to change

isinteger(x::FixedPoint{T,f}) where {T,f} = (x.i&(1<<f-1)) == 0

to

isinteger(x::Fixed{T,f}) where {T,f} = (x.i&(1<<f-1)) == 0
isinteger(x::Normed{T,f}) where {T,f} = (x.i%(1<<f-1)) == 0

[johnnychen94]

This looks good (though I don't quite understand the magic shifting operations here), could you open a PR on this?

Thanks