Explain why image-min isn't used
Explain why image-min isn't used

Added a short paragraph on why imagemin isn't used in the gulp starter, and some recommendations on what to use instead.
greypants/gulp-starter,jakefleming/mezzotent,greypants/gulp-starter,greypants/gulp-starter,greypants/gulp-starter,jakefleming/mezzotent,vigetlabs/gulp-starter,jakefleming/mezzotent,vigetlabs/gulp-starter,jakefleming/mezzotent,vigetlabs/gulp-starter,vigetlabs/gulp-starter