Don't keep accumulating pages once we've hit max_entries, that's
supposed to limit the pages we acquire for the LRU queue.

Replace the file counting mechanism for restarting at the same
spot in the dhandle list with a reference to a field of the
dhandle structure.
Merge branch 'develop' into evict

Conflicts:
	src/include/cache.h
If a page was once modified, we can still fast path it if the maximum
transaction written for the page is globally visible.
Don't call __wt_evict_list_clr_page() if it's the top-level page.  This
is an optimization (and it's not needed since __wt_evict_list_clr_page()
checks WT_PAGE_EVICT_LRU before it does any real work).  I'm putting it
in more for clarity than anything else, it confused me for awhile why
the top-level page was still on the queue.
Just use the dhandle for evict_file_next: that's just as unique as the name pointer.
Merge pull request #735 from wiredtiger/evict

Minor bug fixes in eviction.