Code review comment for lp:~zorba-coders/zorba/f-nosql-db-trunk

According to Cezar:

> Comment from Matthias:
>
> - rename delete-value function to remove to be consistent with Couchbase
> - document errors that may be raised by the functions

Both done.

> - can we make the get and put functions take sequences of keys and values,
> respectively
> (e.g. nosql:get-text($db as xs:anyURI, $keys as object()* ) as object()*)

There are 3 kinds of functions in this module:
- convenience functions for working with strings as keys, just like a java Map.
- raw that gives access to major and minor key components
- and advanced called multi-* that gives access to sub-ranges of keys.

I rather not add the $keys as object()* to avoid confusion with the multi-* functions that use sub-ranges.