Add get/set while being a provider.
Add get/set while being a provider.

Should fix #16.

kknirala/ngStorage,wyvern8/ngStorage,GerryFudd/ngStorage,lalithr95/ngStorage,gsklee/ngStorage,robinboehm/ngStorage,BaggersIO/ngStorage,wodka/ngStorage,castle-it/ngStorage,prudvihemanth/ngStorage,4talesa/ngStorage,bratishchev/ngStorage,egilkh/ngStorage,JulienBier/ngStorage,imskojs/ngStorage