v0.20

• Added flag to allow disabling of pattern factorization.
• Improve pattern factorization by only hoisting labels that get jumped to from more than one place.
• Improve pattern factorization by generating fewer ifs in cases where the conditions can be merged into a single if + and.
• Compile chains of cons calls that result in a properly formed list into a single list call.
• Multiple aesthetic changes to the Scheme code the compiler generates.