Separate the btree maximum key/value sizes from the underlying page
size, reference #1282.

Deprecate the internal_item_max and leaf_item_max configuration strings,
replace with internal_key_max, leaf_key_max and leaf_value_max.

Remove examples/c/ex_file.c (there's no real need for a "file" URI
example, and it's easy to replace the one place the documentation
used it).
Merge branch 'develop' into overflow-relax
Remove the min / max bounds on overflow sizes.
Merge branch 'develop' into overflow-relax
Merge branch 'develop' into overflow-relax
Merge branch 'develop' into overflow-relax
Rename page_size_max to page_size_orig, clarify its usage (raw
compression is the only thing that cares).
When I switched the tracking frequency from 1/10 of a second to 1/4
of a second, I didn't update the code that decremented the timer to
the end of a run -- fix it.
Make every 1000th record big (80-100KB).
We can't use the corrected page size to calculate the buffer's space
available, but we don't have a page size either. We do know how much
space we added, so use that to increment the space available.

The raw compression handler can no longer pass a page size buffer to the
underlying compression function, because a single key/value object could
be larger than the page size, instead, pass a buffer of the same length
as the source to compress, whatever that is.
Merge branch 'develop' into overflow-relax
Another pass over the wording.
Merge branch 'develop' into overflow-relax
Rename onpage_ovfl to key_onpage_ovfl to make the two row-store
routines match.
Add an example a large leaf-page value overflow config
Fix a comment.
Fix the example, missing comma.
Changed python test suite to allow for shorter runs by default,
with a --long (or -l) option for the complete runs.  Txn02 in particular
now runs only a small number of scenarios by default.  Also added a
@longtest("description") decorator for individual tests that can be
marked to be run only under --long.  Refs #1461.
Allow pruning scenarios with different limits for default vs. long runs.
The pruned scenario list now matches the original ordering.
Tests now print with both the scenario number and the scenario args.
This should make it easier to diagnose and debug problems that effect
only certain scenarios.  Refs #1461.
Used prune_scenario limit the number of scenarios for default test runs.
Refs #1461.