implement update_sector opcode
add UpdateSectorInput()
include consensus support for uploading, but without api support.
add api support for uploading a file
add sector file copying to HandleEvent
add api call for downloading a wallet sector
remove ParentHash as a requirement for uploads
implement uploading in the client
add testing for state/erasure.go
fix download issue
Merge pull request #205 from DavidVorick/updates

Uploads and Downloads