4.0.0

• To properly work with electron-builder the applicaiton source code has been split into two folders: src and app. See readme for longer explanation. As a byproduct of this change builds are now much faster (no need for copying static files like node_modules folder).
• Using now rollup incremental builds (faster rebuilds in gulp watch tasks).
• If any gulp task in watch mode will fail sound is played in terminal to let you know.
• Using now electron (not electron-prebuilt) npm module.
• Gulp build process no longer has clean task.
• Unit tests now respect source maps when raporting errors