An initial start to add directory support, looking to get help/advice from community to make code more robust.

Added capability to prefix key with directory for get, set, has, remove (i.e. "testfolder/foo" will get, set, has, or remove foo under the testfolder directory).
Also extended functions getAll, keys, clear* to allow optional directory parameter (i.e. "testfolder" will getAll, keys or clear* under the testfolder directory.

getMany is tricky and needs some work.

*Currently clear removes the directory passed to function.
**All current test cases pass with exception of utils test function since directory is different