Slight error in tocks for 25FPS fixed

[mikemccauley]

In RMT.ino, the clock divisor is set to 3 with:

#define DIV 3

However, when FPS is 35, this results in a small error in the clock rate.
Suggest instead you change it to this:

#if (FPS == 25)
#define DIV 2 // MIKEM: this was 3, but that introduces a small bit rate errors for 25 FPS
#else
#define DIV 3
#endif

Which results in exact tock rates for 25FPS