verify certs during the fetch process, by asking for consistency proofs at the end of each batch
- this temporarily breaks the fetch behaviour since merkle tree hashing is not yet fully-implemented
better error catching and docs for new method on LogClient
add tests for get_sth_consistency and shortcut the trivial cases
add separate MonitorState field for the verified partial STH of the current batch
- move low-handling state-handling code into separate utilities and bunch them together
- force pending_sth > verified_sth and have _update ignore non-pending rather than assert pending
fix tests
- change the temporal consistency check to a full check since that's what we're now doing in the monitor
- improve docs for MonitorState
allow same-size STHs, consistent names for MonitorState functions, and other review comments
add flag to temporarily disable consistency checking since merkle tree hashes are not yet implemented