query.c: Added support for filtering by keyword score ranges

This can be used in conjunction with keywords like "rank" to filter results by
ranges of ranks.

Signed-off-by: Morten Hustveit <morten.hustveit@gmail.com>
Merge branch 'master' of https://github.com/mortehu/cantera-table
table-backend-writeonce.c: Initialize "middle" variable in binary search

If the entry count of a table was zero, the function could incorrectly report
success.

Signed-off-by: Morten Hustveit <morten.hustveit@gmail.com>
arena.c: Added missing #includes

va_start, va_end and vsnprintf require <stdarg.h> and <stdio.h>

Signed-off-by: Morten Hustveit <morten.hustveit@gmail.com>
table-backend-writeonce.c: Return 0 from seek_to_key when key is not found

The previous logic was simply faulty.

Signed-off-by: Morten Hustveit <morten.hustveit@gmail.com>
tests/wo-sort-00.c: Replace an assert with a graceful exit

The asserts leave temporary files dangling.

Signed-off-by: Morten Hustveit <morten.hustveit@gmail.com>