v1.5.2

v1.5.2 focused on improvements to saving and retrieving patterns at three different levels of scale:

1. Internal patterns accessible during the generation of a FacetPattern, via new methods setlocal() and getlocal().
2. Global patterns via improved set() method.
3. Creating and continually modifying patterns each loop in a process, via new drift() method, where the coder can specify the changes to apply to the pattern each loop.

Bug fixes / improvements:

• improved implementation of walk() method. In its previous implementation, it would tend to converge onto a single value from the pattern if run recursively.