Updated package.json to use 4.0.x - https://github.com/isaacs/node-semver
server config migration to 4.0

Removed unused middleware
Support no files present

When no wallpapers/files were present app would throw error. Fixing for
now but 'files' will be removed. For that look into the 'refactor'
branch
Merge pull request #16 from Dudemullet/update_express_4

Update to express 4