fix: persist data to disk

fix(package): update pouchdb-collections to version 6.0.4 (nolanlawso…

…n#10)

https://greenkeeper.io/

fix: does not crash when folder removed before debounced write

feat: allow folders in dbname

BREAKING CHANGE:

Before, all datbases have been stored in `.fsdown`, configureable by `require(fsdown).directory`. Besides that, all database names have been sanitized, so `myfolder/dbname` would become `myfolderdbname`

`require(fsdown).directory` has been removed, and dbname can now contain folders. It is split using `.split(require(path).sep)` and all parts are sanitized separately.

1.0.1