Put the 3rdparty directory at the beginnging of the Python library path, so our local version overrides any installed one.
Split chunk selection out of LSM merge function.
Don't give up locking a handle just because it is open.  Only fail if it is open and we can't get exclusive access.

refs #1336, #1368
Have LSM cleanup bloom filters consistently.

There were cases before that old bloom filters could
interfere with creating new chunks.
Fix build warnings re: uninitialized variables.
Fixup per review comment.
Don't reset session random number generations, applications that don't
cache sessions will end up generating bad skiplists because their random
numbers will be the same on every update/insert.
Merge pull request #1371 from wiredtiger/lsm-merge-simplify

Lsm merge simplify
whitespace
Merge branch 'develop' into incremental-backup