ccl_leveldb should be abstracted out of this package.

[AlexC-CCL]

As the leveldb module is useful for other, non-chrome artifacts, it's wrong that this package should be the only public method of getting it. It should be moved to its own module. This would also remove ccl_simplesnappy as a direct dependency for this module.

[sheindel]

Hi Alex. I've been doing some work in Chrome and have written some basic indexeddb utilities, but I really appreciate the thoroughness of this library, and would definitely appreciate ccl_leveldb as a standalone library. Is this something you expect to maintain under the cclgroupltd github org or under a separate org?