Replace the C-style typless macros in config.hpp with C++-style const
definitions.

All tests now pass again. :)

Test of the recent slots filled are now working correctly.

Yeah, P2P works now, as far as I can tell. Nodes connect, sync, and stay
in sync. Not rigorously tested yet, but the basics are there.

Dunno what happened, but I don't have time to fix it right now.

Fix the stuff that broke in merge.

Define a new p2p_plugin as the adaptor between appbase and the old P2P
library, and wire things together. This is mostly working, but for some
reason peers won't stay connected to sync, but instead just drop their
connection (with a TCP reset, no less) right before syncing, without
bothering to log about why. I suspect the failure is at a lower level. :
(

Remove the new types library temporarily, until the missing sources are
checked in, so that builds work again.

The producer plugin (now called producer_plugin) is now adapted to the
new appbase system, and appears to be working correctly.

Also, eliminate some boilerplate around OBJECT_CTOR macro! Now you can
OBJECT_CTOR(objname, (field1)(field2)) to indicate that field1 and field2
are dynamically allocated objects and need to be initialized with the
allocator.

Bring in chain_plugin, net_plugin, http_plugin; wire appbase and plugins
into existing infrastructure, remove old app infrastructure.

As discussed on #5, use hashes as the generated_transaction_id_type
instead of serial numbers.

Define structures around cycles/threads, etc.

Also implement merkle digests. :)

Add prose explaining what each test does, and inline comments where
appropriate.

Add structs and types to facilitate the explicitly declared authority
level described in issue #2.

May or may not be revisiting this to tweak it later... :P

Previously, the fork_database and chainbase undo histories were never
getting trimmed, so they'd grow forever. Fixed.

Also some improvements around how to use chainbase, particularly,
setting the revision after a reindex, and also acquiring locks
appropriately. Note that there's a lot of lock acquiring that still
needs to be added; I didn't realize I needed to do this before :]