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.
Minor cleanup. #1447
Have LSM worker reconfigure work with min workers.

References #1460.
Fix copy-paste error.