Firefox build support

After having multiple emails back and forth with the Firefox support team, they've decided to remove the application from their store since the build process was not fully reproducible because of the webpack hashes, this release solves that problem thanks to #16 by @GrosTon1. The release also includes a few small fixes.

Night Mode

After the initial v1.0.0 release, I have received some nice pull requests to fix some CSS issues for responsive design, which are merged. Also, there was an issue from a user that points out the need for a Night Mode, which is implemented with this release as well.

Therefore, this release contains:

• Horizontal and vertical scroll fix, which is here #2, thanks to @luanmuniz.
• Responsive card sizing with #5 and #7, thanks to @hipstersmoothie.
• Night mode implementation, closing #4.
• Increased test coverage for visual aspects of the cards.