My suggestion for improvement would be not to use an L293 in the first place: why would a "Specialist in Industrial Automotation" use something that's what 30? years old when there are so many more efficient solutions available?
I daresay Pololu have a suitable one here.But why do you need a library to use a 293? The Y outputs follow the A inputs: make eg input 1A high and output 1Y goes high. Write a couple of functions (forward(), reverse(), whatever) in your sketch to make the right pins high and low to get the right motor directions.You could make the conversion of such functions to a library into a more advance exercise.