String uses copy-and-swap idiom

github issue #17
and move constructor github issue #13
Array uses copy-and-swap, move ctor

github issues #17 and #13
Dict uses copy-and-swap, move ctor

github issue #17 and #13
move ctor

github issue #13
List uses copy-and-swap, move ctor

github issue #17 and #13
Ref uses copy-and-swap, move ctor

github issue #17 and #13
oolib requires C++11