Dev.to daily challenge Duplicate Encoder

[Jesse Phillips]

The Dev.to community does a Daily Challenge[1]. I didn't really 
set out to solve the  problem and instead took the top 
implementations done in different languages and implemented them 
in D[2].

I need to emphasize I reference languages but this is not 
performance of those languages all data is from D. Also I did not 
play too much with optimizations on the compiler (using LDC) but 
feel free to recommend a change.

I find the changes to Haskell's performance to be interesting as 
it went from very unreasonable to competing with Go (Ranges vs 
foreach)

This was just a fun little experiment.

1. 
https://dev.to/thepracticaldev/daily-challenge-259-duplicate-encoder-2e8l
2. https://github.com/JesseKPhillips/devto-challenge259-dupencoder