Bump the LSM generation just before releasing the lock.  In particular, don't bump it before checkpointing the metadata.
Fix a bug tracking the bytes allocated for old LSM chunks.
Reduce the number of cursors that are closed and reopened when an LSM tree is updated.
Do LSM switches in the worker unless the primary grows much too big.
Fix a possible divide-by-zero in the LSM throttle calculation.
Use the condition variable to signal the worker thread when a switch is required.
LSM worker threads don't need to check the state so often: increase sleep times.
Add a comment about how we realloc the arrays inside cursors.
Fix the logic for waking the LSM worker thread: do it the first time we notice a switch is needed.
Merge pull request #514 from wiredtiger/lsm-latency

Changes to improve latency of LSM operations
Wait on a condition variable rather than sleeping in LSM workers.  This can be signalled during close, speeding up tests that open and close many LSM trees (such as test/fops).