use sort.Search

Signed-off-by: Joshua Rubin <joshua@rubixconsulting.com>
make Slice its own type and move binary search to its Find method

Signed-off-by: Joshua Rubin <joshua@rubixconsulting.com>
make gil.Interface sortable with sort.Sort

Signed-off-by: Joshua Rubin <joshua@rubixconsulting.com>
reorganize packages and tests

Signed-off-by: Joshua Rubin <joshua@rubixconsulting.com>