Add function sincospi

[sostock]

No description provided.

[codecov-commenter]

Codecov Report

Merging #10 into master will increase coverage by 0.16%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master      #10      +/-   ##
==========================================
+ Coverage   97.56%   97.72%   +0.16%     
==========================================
  Files           1        1              
  Lines         164      176      +12     
==========================================
+ Hits          160      172      +12     
  Misses          4        4              

Impacted Files	Coverage Δ
src/HalfIntegers.jl	97.72% <100.00%> (+0.16%)	⬆️

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