Adds toString to Sized #131
Adds toString to Sized #131

Adds toString by delegating to underlying container.

notxcain/shapeless,clhodapp/shapeless,lukasz-golebiewski/shapeless,Atry/shapeless,liff/shapeless,joescii/shapeless,TomasMikula/shapeless,tek/shapeless,milessabin/shapeless,wheaties/shapeless,triggerNZ/shapeless,isaka/shapeless,roberth/shapeless,fthomas/shapeless,malcolmgreaves/shapeless,alexarchambault/shapeless,lambdista/shapeless,khronnuz/shapeless