Fix gulp-useref dependency

The useref package has been unpublished on npm.org in favor of node-useref. Bump the version of gulp-useref that has this fixed dependency, at least v 0.4.2.
Merge branch 'ringods-patch-1'
fix(gulp): Remove gulp-conventional-changelog

Got removed from NPM, breaks the build.

Updated the changelog accordingly.
Updated version for NPM [ci skip]
Major overhaul of the gulpfile

This is a major overhaul of how the gulpfile functions and works,
changes include moving to BrowserSync for auto-reloading, simplifying
command line calls and adding a whole bunch of new packages to the
package.json file.