Made write_t::durability() endemic, made it return DURABILITY_REQUIREMENT_DEFAULT.
Moved protocol.hpp include out of metadata.hpp.
Made broadcaster_t::spawn_write obey write_t::durability() requirements.
Merge branch 'next' into sam_716
Made rdb_protocol_t::write_t point_replace_t constructor require durability_requirement_t argument.  Made things pass it down except for insert_term_t, and replace_term_t, which hard-code the value to DURABILITY_REQUIREMENT_DEFAULT.
Merge branch 'next' into sam_716
Made the write_t constructor taking a batched_replaces_t require its durability_requirement_t argument.
Made write_t constructor that takes point_write_t require its durability_requirement_t parameter.
Made write_t constructors for sindex_drop_t and sindex_create_t not take a durability_requirement_t parameter.  Made point_delete_t require its durability_requirement_t parameter.
Merge branch 'next' into sam_716
Give optargspec_t have an initializer_list constructor.
Removed templated optargspec_t constructor that takes array.
Removed two-argument size-and-pointer optargspec_t constructor.
Merge branch 'next' into sam_890

Conflicts:
	src/rdb_protocol/op.hpp
Fixed or suppressed petty cpplint warnings.
Merge branch 'next' into sam_890
Made insert and replace directly respect their optargs.
Made parse_durability_optarg not be copy/pasted in insert_ and replace_term_t.
Made RSI comment about update and delete passing along optargs.
Removed default_value parameter from optarg.

It was always counted_t<val_t>().