Add an extra check for event.which is 91 // Related to #662
Adds support for oversharding in unittests.
Adds a test which reveals to oversharding bug.
Ostensibly fixes oversharding bug. (#606)

Adds another constructor for rdb_rget_depth_first_traversal_callback_t
which filters out keys which fall outside of a range.
Adds oversharded versions of rdb_protocol tests.

They all pass btw.
Adds comments about different constructors.

The rdb_rget_depth_first_traversal_callback_t now has 2 different
constructors, this adds comments which clarify what each is intended
for.
Fixed type of limit and zip (c.f. Issue #678).
Fix a typo.
Adds a unittest to expose issue_690.

This exposes an issue that arises when sindex post construction is
interrupted due to the store being deleted.
Adds a potential fix.
recreating sindex map on startup so sindexes work if the server is restarted
adding a comment clarifying dummy_interruptor use in btree_store_t constructor
adding sindex continuation of post-construction in rdb_protocol following a server restart that interrupted post-construction
checking for missing web assets directory before failing a guarantee
fixing missing return on sindex not found
Fix the rule for compiling protobuf files (#693)
Merge review 421 by @mlucy
Merge branch 'next' into michel_662_command_key
Revert "Fix the rule for compiling protobuf files"

It breaks the build

This reverts commit f05e7c34e639b2f237faec467f4e51b77433f87d.
Merge branch '678_fix_limit_type' into next