Makes between followed by order_by not drop the between.

All existing tests pass. Now it's time to write tests for the new
behavior.
Adds tests which fail for order_by and between.
Adds more failing tests.
Merge branch 'order_by_between_test' into order_by_between
Makes for chained order_by and between pass.
Add a failing test for get_all and order_by.
Make order_by not drop get_all.

Also adds tests which test this.
Pass rcheckable_t *s rather than backtraces.
Fix a bug with referencing sindex_id rather than _sindex_id.

Also renamed _sindex_id to make this mistake less likely.
Redo an error message.
Improve an error message to reference indexes.
Add tests for unindexed order_by followed by indexed.
Merge branch 'next' into merge_br