KNF
Increment the page's memory before releasing the serialization mutex,
regardless, don't free the memory until after the release.  Ref #393.
Add a statistic to track the maximum depth of the tree, as measured by the
deepest we ever search.
Add shared cache option validation to reconfigure.
Ensure cache pool reconfiguration is honoured quickly.
Check the 'bulk' configuration value for invalid strings.
closes #434
* * *
Remove the link from the docs to the old github "downloads" page.
Remove the link from the docs to the old github "downloads" page.
Make single-threaded populate in wtperf into a bulk load.

This isn't part of the test that we typically report, it has no bearing on LSM performance, and it cuts down the time to get results for btree by at least an hour.