Something happened during rebase. This configuration is supposed to be
True by default now.

received docs makes no sense for a single request download, plus all its
comments and docstrings. Also updated docstrings for other methods.
The method that tests if sqlcipher is encrypted can return a db handle
that can be used right away. If we ignore it and reopen we can end up
with a lost open cursor.

Request size on a stream can't be measured upfront and a limit doesn't
make much sense. The real limit is user's Quota, to be implemented.

Moved out magic numbers into a constant and simplified logic during doc
upload.

batch is slower than usual insert for a single doc, so, if a document
exceeds the buffer, commit the batch (if any) and put the huge load by
traditional insert.
refactor coming.