minor refactor to ensure that we can begin lisening to changes to the
payment queue at application launch
put timer back
no opps
removed unecessary code
initialize variable
organizing some methods.    NO OPP CHANGES
ifdef out ios related code
processing a trnasaction happens in a single location
using NSError instead of strings
finishing a transaction after it failed
using NSErrors for fetching products
checking for an error before converting it to a C++ string, which will
cause an exception
Merge pull request #32 from lumoslabs/turner/IAPfix

(DO NOT REVIEW) turner / refactor to allow listening to apple for IAP all the time