Include typescript source in npm package

[jonaskello]

This PR will include the typescript sources in src/ in the published npm package. We were already including *.map files but when eg. webpack tried to load them the referenced typescript files in src/ were not found so webpack emits a warning.

The choice is either to make a special production build without source maps and publish the *.js files without any sourcemap refrences, or include everything in the npm package. My reasoning here is that if we include everything it will be easier to get god stack traces and debug.

[codecov]

Codecov Report

Merging #8 into master will not change coverage by %.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master       #8   +/-   ##
=======================================
  Coverage   99.35%   99.35%           
=======================================
  Files         142      142           
  Lines         934      934           
  Branches        1        1           
=======================================
  Hits          928      928           
  Misses          5        5           
  Partials        1        1           

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