refs #127 Add a bit to enable/disable thread local allocations
refs #127 Use a scoped allocation when serializing a non-leaf node for
partial eviction
refs #127 Use a scoped malloc during serialize
refs #127 Use scoped malloc during rebalance
This is a big commit with stuff to get rid of
fixes #132 Calculate size delta statistics once during the partial
eviction callback
fixes #142 Always use quicklz when partially evicting an internal node
partition
fixes #140 Pre-size the fifo before appending data during nonleaf
serialization. Assume the fifo is about 1kb larger than the read buffer
(in practice, the fifo is 5 bytes smaller than the read buffer).
fixes #130 Create the message trees without an underlying array when
first creating a nonleaf childinfo. Later, deserialization will replace
those empty OMTs using the create_from_sorted_array() constructor.
Remove dead code
Add local thread id to the frwlock to simplify debugging pair-lock
related pileups.
fixes #145 Add a finalize continuation to the partial eviction callback
which encapsulates the 'function ending' behavior of eviction - changing
the pair's attribute and releasing locks. After finalize continuation,
it's safe to do expensive resource deallocation (but contract forbids
continued use of the ftnode, since it's not locked)
fixup

Conflicts:
	portability/memory.cc
Add a context class for tracking what a thread is doing. This is the
first step towards generic instrumentation for frwlock contention.

Conflicts:
	util/frwlock.cc
	util/frwlock.h
Add context engine status entries

Conflicts:
	util/frwlock.h
refs #146 Set context in various places, add a context to the current
writer in a fair rwlock
Add new contexts, add define for switching between nonleaf partial
eviction strategies

Conflicts:
	ft/ft-ops.cc
	util/context.cc
Add context for partial fetch in another pin API
Add context for HOT
Conditionally compile in query histograms

Conflicts:
	ft/ft-ops.cc