Minified file not copied in target/www/

Minified artifact was not added to www folder (and thus not in .zip)

* Changed minification output file to target/www/artifact-min.js (as aggregated file)

* After minification, copy target/www/artifact-min.js to target/artifact-min.js

Signed-off-by: nicolas-rempulski <nicolas.rempulski@gmail.com>
Updating .gitignore

Signed-off-by: nicolas-rempulski <nicolas.rempulski@gmail.com>