support unicode string display

[leslie-wang]

Signed-off-by: Leslie Qi Wang leslie.qiwa@gmail.com

• [Y] I've read Contribution guide
• [T] I've tested everything that doesn't relate to tcell.Screen API

Close #76

[codecov-io]

Codecov Report

Merging #77 into master will decrease coverage by 0.78%.
The diff coverage is 75%.

@@            Coverage Diff             @@
##           master      #77      +/-   ##
==========================================
- Coverage     100%   99.21%   -0.79%     
==========================================
  Files           7        7              
  Lines         248      255       +7     
==========================================
+ Hits          248      253       +5     
- Misses          0        1       +1     
- Partials        0        1       +1

Impacted Files	Coverage Δ
interactive/reporter.go	96.87% <75%> (-3.13%)	⬇️

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[viktomas]

@leslie-wang thanks for another contribution! It's great to see the handling of edge case like this. Please make sure you add tests for all code that you add.

Could you please check whether it would be possible to use the native range loop or the native utf8 library to avoid adding unnecessary dependencies?