GitLab

__init__(): FullLog must now maintain a list of created versions so
that the Berkeley storage can query it when it's got a version string
it doesn't know about.  Otherwise, we'll just create multiple
create-version entries in the log.

finish(): clear the __versions dict.

get_vid(): Look up a version string, returning the associated vid, or
None (by default).

write_object(), write_nonversion_object(), write_moved_object,
write_new_version, write_discard_version(): Higher level interface to
adding new commit log entries.  There's really only three record
types, but it helps to have the higher level API.

next_object(): Get the next entry in the commit log, but assert that
the key is one of `o', `v', or `d'.

Also, fix a typo and get rid of the old store() and storeNV() methods.