refactor range_entries and rev_range_entries
more (rev_)range_entries refactoring, expose range_ascending and range_descending
feedback from PR
Merge branch 'range' of https://github.com/domsj/camltc into domsj-range

Conflicts:
	src/otc.ml
fix reading of empty ranges
Merge pull request #11 from domsj/fix-range

fix reading of empty ranges
expose more cursor operations (out,jump)
Merge branch 'master' of github.com:toolslive/camltc
Update tokyo cabinet link in readme
Merge pull request #12 from domsj/master

Update tokyo cabinet link in readme
bugfix: jump
should use tcbdbcurjump iso tcdbcurjump2
Merge branch 'master' of github.com:toolslive/camltc