fixes #201

We needed to be more careful about extracting archives which may
contain multiple objects with the same name.

initialize it for full gc if we think it is worth it. This allows for
full gc to run when bringing a basement node up to date.

there may be an abort message waiting to be applied.

in a different order than they began, and blow up a bad assert.

separate the difference between the oldest referenced xid we can use for
implicit promotion vs simple garbage collection.

run full garbage collection when a leafentry has > 1 committed entry.

node and notices that it is over 32mb

osx doesn't support __thread well so scoped_malloc breaks it.  Rather than
fix it, we implement a correct but poorly-performing implementation for
now that will be used on osx machines.

fixes #160

Refs Tokutek/ft-index#159 Calculate klpair size correctly when message application deletes a leafentry

Refs Tokutek/ft-index#159 Calculate klpair size correctly when garbage collection deletes a leafentry

Garbage collection was done on the clones and did not always make it to in-memory.
Also, closing a db and reopening no longer (necessarily) flushes the nodes out of memory; we close the entire environment when we want to ensure we read it.

partial eviction

thread-local buffer when possible.

frwlock

refs Tokutek/mongo#886, change get_last_key to use a callback instead of copying data, so that we don't have
mongo code freeing data that fractal tree allocated.

Add db->get_last_key() and test.
Add test

partition

eviction callback

serialization. Assume the fifo is about 1kb larger than the read buffer
(in practice, the fifo is 5 bytes smaller than the read buffer).

create_no_array() so that deserialization does not malloc/free needlessly.

logger