Add convert(Interval, x::String) and Interval(x::String) about intervalarithmetic.jl HOT 4 CLOSED

I think they do, though I am not sure if this is what the standard dictates:

julia> convert(Interval{Float64}, "0.1")
Interval(0.09999999999999999, 0.1)

julia> @interval 0.1
Interval(0.09999999999999999, 0.1)

from intervalarithmetic.jl.

The following are missing for a String s:

• convert(Interval, s)
• Interval(s)
• parse(Interval, s)

from intervalarithmetic.jl.

parse(Interval, s) = parse(Interval{default_precision()}, s)
Interval(s::String) = prase(Interval, s)
convert(::Type{Interval}, s::String) = parse(Interval, s)

should be straight-forward since all pieces are implemented (both in 1.0-dev and master)

from intervalarithmetic.jl.

It is 6 years old, and it seems that there is just no need for adding a constructor in the vein of interval(s::String) = parse(Interval, s).

@lucaferranti, since you were the last one to look at this issue, feel free to re-open it if you are still planning on implementing this.

from intervalarithmetic.jl.