Implement Array#slice and Array#slice!
Use space.subscript_access() better.
Implement Array#uniq and Array#uniq!
Fix some translation errors.
Rewrite Array#uniq! in Ruby so the JIT can see into it.
Simplify Array.uniq! now that it is Ruby rather than RPython.
Merge pull request #389 from jerith/jerith/array-slice

Implement Array#slice(!) and Array#uniq(!)