Update gulp build task to preserve icons for electron-builder

[vicatcu]

In the tasks/bulid.js file, you can change:

let paths = {
  copyFromAppDir: [
    './node_modules/**',
    './www/**',
    './routes/**',
    './**/*.+(jpg|png|svg)'
  ]
}

to

let paths = {
  copyFromAppDir: [
    './node_modules/**',
    './www/**',
    './routes/**',
    './**/*.+(jpg|png|svg)',
    './icon.ico',
    './icon.icns',
    './background.png'
  ]
}

... so that those icon resources can be put in the src folder and they will end up in the build folder for the benefit of electron-builder packaging.

I'm actually still fighting to get electron-builder to build an executable for me on Linux, but this is probably part of the puzzle anyway. I'm getting:

{:timestamp=>"2017-06-07T15:49:40.251127-0400", :message=>"Invalid package configuration: Cannot package the path '/tmp/electron-builder-wew21A/0-1-linux.iconset/icon_256x256x32.png', does it exist?", :level=>:error}

[vicatcu]

FYI, got past that last problem by generating the icns file on a Mac instead of trying to synthesize it from a png using a website converter.

[paulsutherland]

Thank you, I have updated as requested.

Thanks for the feedback.

Paul