Publish generated source maps to NPM (#568)

Author: mdwheele

.npmignore

@@ -26,7 +26,6 @@ a_reference
 .nyc_output
 jest
 /coverage
-*.map
 .coverall.yml
 /uploads
 /greenkeeper.json
@@ -39,4 +38,4 @@ README.md
 tsconfig.json
 TODO.md
 build.sh
-launch.json
+launch.json