Made in/out event watchers be pulsed upon error mask.
Merge branch 'v1.4.x' into sam_639
Moved batch_replaces_fifo_sinx above the drainer in rdb_batched_replace.
Made intrusive_list_t::validate function be const.
Added debug variables initialization_attempts_ and mod_report_call_count_.
Added more mrcc and coro_count guarantees.
Fixes a potential problem with deleting and recreating a sindex.

Fixes #657.
Added token_pair->sindex_read_token.reset to the distribution_read_t rdb_read_visitor_t method.
Removed sindex_read_token resetting and added yields for now.
Added value and thread info to guarantees about mod_report_call_count and initialization_attempts_.
Added exiter.wait to do_a_replace_from_batched_replace, fixing the second part of #666, it seems.
Removed a bunch of debugging cruft.
Merge branch 'next' into sam_666
Made object_buffer_t not inherit from home_thread_mixin_t.
Made object_buffer_t use variadic templates for some reason.
Merge branch 'next' into sam_666
Fix for #691
Merge branch 'next' into merge_br
Add simple --ccache option to ./configure
Fixed type of limit and zip (c.f. Issue #678).