Create contants for parmeters

[rboeije1]

Looking at the generated code, I noticed that if the length is 60, 60 is used as parameter to all functions and references to the strip length. If you do a 'const int stripLength = 60' or '#define STRIPLENGTH' at he top and use that, the generated code can easily be modified (And understood by the beginners) The same for some other constants, like the pin number to use and the delay.