Update 04-introduction.tex
Update 04-introduction.tex

amendment to the Introduction
kaathleen/LeapGesture-library,kaathleen/LeapGesture-library,kaathleen/LeapGesture-library,kaathleen/LeapGesture-library,kaathleen/LeapGesture-library,kaathleen/LeapGesture-library,kaathleen/LeapGesture-library