Reword a comment for clarity.
Allocate the underlying WT_ROW, WT_COL and WT_REF page structures
as part of the WT_PAGE allocation, hopefully resulting in fewer
(and larger) memory allocations when pages enter/leave the cache.
Create a cached list of WT_EXT structures in order to avoid so many
allocation calls.
Minor doc change.
We're not necessarily holding the live system's spin lock when we
discard extent lists, don't involve the cached WT_EXT list.
If __wt_block_extlist_free() doesn't access the live system's cached
WT_EXT lists, it doesn't need a WT_BLOCK argument, clean all that up.
Merge branch 'develop' into less-allocation

Conflicts:
	src/btree/bt_page.c
Merge pull request #480 from wiredtiger/less-allocation

Reduce the number of times we allocate memory.
Fix a (dumb) gcc warning:
src/btree/bt_page.c:243:21: error: 'alloc_entries' may be used uninitialized in this function