Gettin' on the Gulp-train

Setup build environments with CLI arguments.
  - default to 'development'
  - pass `--env [p|prod|production]` for 'production' mode

Styles
  - compile SCSS
  - concat into single file
  - autoprefixer
  - minify (CSSO, in 'production' only)
  - remove unused styles
  - rev/rename filenames (append hash, in 'production' only)

Scripts
  - JSHint
  - concat into single file
  - uglify (in 'production' only)
  - rev/rename filenames (append hash, in 'production' only)

Images
  - minify/optimise
  - rev/rename filenames (append hash, in 'production' only)

HTML
  - copy to build/
  - minify (in 'production' only)

Server
  - start browserSync server with livereload on port 3000
  - watch asset directories for changes

Token replacement in HTML/TXT files

Import content