Remove dist from gitignore

Since there is no `.npmignore` file, [npm will use `.gitignore` instead](https://docs.npmjs.com/misc/developers#keeping-files-out-of-your-package), which causes the dist files to be ignored.

Author: wadetandy

.gitignore

@@ -49,7 +49,6 @@ jspm_packages
 *.swn
 *.swo
 
-dist/*
 tmp/*
 !tmp/.keepme
 !.keepme