Enable Bolt 3.0 and 4.0

[majensen]

This PR enables a large portion of Bolt protocol versions 3.0 and 4.0. Additional functionality is also added to the shell client to take advantage of explicit transactions (3.0+ :begin :commit and :rollback) and of having multiple databases (4.0+ :dbname).

[majensen]

Looking forward to a review of this work- thanks!

[majensen]

@cleishm thinking about having a look?

[cleishm]

Definitely thinking about it! ;-) Sorry, been very busy with my day job lately. I'll try to peek at it this week.

Once we get this reviewed and merged, we should chat about opening this repo up to other maintainers as well - like yourself?

[majensen]

@cleishm would be an honor! I would have to actually learn C then--