* refactor cleanupRDKitCache for readability
* fix the indentation
* add comments
* add some comments
* allocate/deallocate the cache holder in the associated memory context
* exit the cache holder memory context callback once done
* more consistent use of the memory context from ValueCache
* refactor the cleanupRDKitCache callback
* minor changes to comments and renaming variables
* refactored Bfp indexing and similarity search
* update CMakeLists.txt
* catch (and fix) inconsistent options around building static libs
* differentiate the data structures in inner and leaf pages
* code cleanup and some additional comments
* version bump
* fix renaming of cache function
* minor cleanup
* add -DUSE_BUILTIN_POPCOUNT to ${POPCOUNTFLAGS}