Remove pattern length restriction

[theGreatWhiteShark]

As discussed in #2001 it would be favorable to drop the restriction of maximum pattern length to 4 * 4/4. I do not see point why this is still relevant.

In addition, we could review some of the variables exposed in CMakeLists.txt. Increasing MAX_NOTES does somehow increase possible pattern lengths too. But in a really weird and glitchy way. Is there something off with handling this variable or is it a bad idea to expose it in the first place.