Always use truncated printing by default

[giordano]

Use IOContext to control the behaviour.

Fix #40 @karlwessel

julia> using Measurements, Unitful

julia> x = pi ± (ℯ/100)
3.142 ± 0.027

julia> (x,)
(3.142 ± 0.027,)

julia> x * u"m"
3.142 ± 0.027 m

julia> println(IOContext(stdout, :error_digits=>0), x)
3.141592653589793 ± 0.02718281828459045

julia> println(IOContext(stdout, :error_digits=>1), x)
3.14 ± 0.03

julia> println(IOContext(stdout, :error_digits=>5), x)
3.141593 ± 0.027183

[codecov-io]

Codecov Report

Merging #43 into master will decrease coverage by 0.33%.
The diff coverage is 81.81%.

@@            Coverage Diff            @@
##           master     #43      +/-   ##
=========================================
- Coverage   96.64%   96.3%   -0.34%     
=========================================
  Files          12      12              
  Lines         537     542       +5     
=========================================
+ Hits          519     522       +3     
- Misses         18      20       +2

Impacted Files	Coverage Δ
src/show.jl	72.72% <81.81%> (-2.28%)	⬇️

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[karlwessel]

Works like a charm:

julia> using Measurements

julia> a = 10π ± π
31.4 ± 3.1

julia> a, a
(31.4 ± 3.1, 31.4 ± 3.1)

Also in legends of plots and everywhere else where i tested.

Thank you!

[giordano]

Cool, thanks for testing!